Sunday, September 20, 2009

Experiment #3: Experimental Procedure

Total time: ~2 ½ - 3 hrs. (excluding overnight chilling)

(Adapted from Tartine by Elizabeth Prueitt and Chad Robertson)

Part 1. Coconut Chiffon Cake

The recipe given below makes one 10” cake, which will be split into three layers to assemble the entire cake.

Ingredients

2 ¼ cup (315g) of all purpose flour

1 ½ cup (300g) of sugar, divided

2 tsp of baking powder

¼ tsp of nutmeg

1 tsp of salt

¼ cup of vegetable oil (ie, safflower or sunflower)

6 large egg yolks (~1/2 cup)

¼ cup of water

¾ cup of unsweetened coconut milk

10 large eggs whites (~1 1/3 cup; at room temperature)

½ tsp of cream of tartar

1. Preheat oven to 325°F and line a 10” x 3” springform pan (bottom x side) with parchment paper. No need to grease the pan.

2. Sift flour and baking powder into a large mixing bowl. Add 1 1/4 cup (250g) of sugar and salt and whisk to combine.

3. In a small bowl, whisk together the oil, egg yolks, water and coconut milk.

4. Make a well in the flour mixture, and add the egg yolk mixture (step 3) to the flour mixture (step 2). Whisk ~1 minute to achieve a smooth, homogenous mix.

5. Place egg whites (room temperature) in a large mixing bowl and place the stand mixer. Using the whisk attachment, beat egg whites on medium speed (“6” on my kitchenaid mixer) until frothy. Then add the cream of tartar, and increase speed to medium-high (“10”) until the whites form soft peaks. Then slowly add the remaining ¼ cup of sugar and keep beating until whites hold firm, shiny peaks.

6. Using a rubber spatula, scoop ~1/3 of the whites into the flour/yolk mixture and gently fold to incorporate everything. Continue to add the remainder of the whites this way just until everything is combined.

7. Pour the batter into the pan and bake for 45-55 minutes, or until a toothpick test comes out clean when inserted into the middle of the cake. Allow to cool in the pan on a wire rack.

8. Once completely cooled, unmold and slice the cake into three layers. To do so, mark 1” segments all along the sides of the cake with a serrated knife. Then carefully cut the top layer first, using the marks to guide. After removing the top layer, proceed to cut the second layer. The cake is ready for assembly. (If not using right away, wrap up tightly in plastic wrap and store in the fridge.

Part 2: Caramel

Ingredients

2/3 cup of heavy cream

¼ of a vanilla bean

1 ¼ cup of sugar

¼ cup of water

¼ tsp of salt

2 Tbsp of light corn syrup

¾ tsp of lemon juice

4 Tbsp of unsalted butter

1. In a small saucepan, add the heavy cream and vanilla bean scrapings together and begin heating to medium-high heat. Bring the mixture to just under a boil, stirring occasionally, then reduce the heat and keep warm until ready for the next step.

2. In a medium saucepan, add the sugar, water, salt and corn syrup (you can begin this step at the same time as step 1). Bring to a boil over medium heat, stirring to dissolve the sugar. Then leave the mixture to continue cooking with no stirring for ~5-8 minutes or until the mixture has become amber colored. Remove from heat.

3. Slowly add the cream mixture to the sugar mixture (boiling will occur). Whisk mixture until smooth, then add the lemon juice and allow to cool ~10 minutes.

4. Add the butter in ~3-4 pieces, one piece at a time, whisking until each piece has been completely incorporated. Continue to whisk the caramel as it cools to maintain a smooth mixture.

Part 3: Pastry Cream

This recipe makes 2 ½ cups of cream…perfect because that’s how much I need to assemble the entire cake!

Ingredients

2 cups of whole milk

½ a vanilla bean

¼ tsp of salt

3-4 Tbsp of cornstarch

½ cup + 1 Tbsp of sugar

2 large eggs

4 Tbsp of unsalted butter

1. Have a bowl and a fine-mesh sieve handy for when the pastry cream is finished.

2. In another bowl (preferably one that has a rubber-grip bottom), whisk together cornstarch and sugar (more cornstarch if you want a stiffer cream). Add eggs and whisk till smooth.

3. In a heavy saucepan, add the milk, vanilla bean scrapings, and salt, and heat on medium-high heat until the mixture is just under a boil. Stir occasionally to make sure that the milk does not burn or stick to the bottom.

4. When the milk mixture has almost reached a boil, slowly ladle 1/3 of it into the egg mixture (step 2), whisking constantly (the rubber grip on the bottom of the bowl should help with the challenge of pouring and whisking at the same time).

5. Pour the egg/milk mixture back into the hot milk, whisking constantly until the mixture thickens (~2 minutes). Continue heating until the mixture is just starting to boil (you should see a few bubbles); be careful not to heat too vigorously or the eggs will curdle.

6. Once the mixture just starts to boil, immediately remove it from the heat and pour the cream through the sieve into the bowl (step 1). (Use a spoon to push the cream through the sieve if its too slow). Cool and stir occasionally to prevent a “skin” of cream from forming on the top.

7. When the pastry cream has cooled to ~140oF (10 minutes), whisk in the butter, one tablespoon at a time. Make sure the butter is well-incorporated into the mix before adding the next.

Part 4: Assembling the Cake

Ingredients

1 Coconut Chiffon cake (Part 1)

Coconut syrup:

1 cup of unsweetened coconut milk

6 Tbsp of sugar

1 tsp of vanilla extract

A pinch of salt

Filling:

1 ½ tsp of gelatin

2 tsp of water

2 ½ cup of Pastry Cream (Part 3)

1 cup of heavy cream (very cold)

½ cup of caramel (Part 2)

Topping:

1 ¼ cups of heavy cream (very cold)

4 tsp of sugar

1. Using a serrated knife, slice the chiffon cake horizontally into three equal portions, removing the top first. (See Experiment #1: Results and Discussion for tips)

2. To prepare the coconut syrup, combine the coconut milk, sugar, vanilla and salt and mix well. Set aside.

3. To prepare the springform pan (10” x 3”), take two large sheets of plastic wrap and stick them together along the long side. Then put the bottom of the pan on top of the wrap, and wrap the plastic wrap into the middle of the pan. Then I placed the outside rim of the pan around the plastic-wrapped bottom. Once the rim of the pan is attached, unfold the plastic wrap and pull it back so that it covers the sides and hangs over the rim of the pan. The result should be plastic wrap covering the inside of the pan, but not the bottom.

4. To prepare the filling: prepare the gelatin by adding 1 ½ tsp. of gelatin with 2 tablespoon of water (gelatin will absorb all the water to form a gel). If the pastry cream is freshly made and still warm, add the gelatin mixture directly to the cream and stir well. Then allow the cream to continue to cool. If the pastry cream is cold: take ½ cup of the pastry cream you just made and add it to a stainless steel bowl placed over a saucepan of water. Warm over medium heat, whisking constantly until hot to the touch (120oF; 5 minutes). Add the moist gelatin, and whisk until it is completely added. Remove the bowl from the water bath and add in the remaining pastry cream in two batches.

5. In a mixing bowl, whip with stand mixer on medium-high setting (“8” on my Kitchenaid mixer) the heavy cream until it holds medium-stiff peaks. Then fold gently into the pastry cream with pastry cream.

6. Place the bottom layer of cake into the prepared pan. Then using a pastry brush, moisten the cake with 1/3 of the coconut milk mixture. Then spoon ½ of the caramel on top and spread evenly. Next, scoop ½ of the pastry cream filling on top and spread evenly with an offset spatula. Place the second layer of cake and repeat the moistening with 1/3 of the coconut milk mixture, adding the remaining caramel, and adding the remaining pastry cream filling. Add the top cake layer, and moisten with the remainder of the coconut milk mixture.

7. Wrap the cake with the plastic wrap from the sides and gently press the cake down to spread the filling evenly. Allow the cake to cool in the refrigerator for 4 hours or preferably overnight.

8. To finish the cake, remove the metal sides and unwrap the plastic wrap from the cake. Place the cake on a raised surface, preferably a wire rack over paper (to prevent a mess). Clean up any stray filling with an offset spatula.

9. Beat the cold heavy cream in a stand mixer set at medium high (“8” on my mixer). When the cream thickens, add the sugar and continue whipping until the cream holds soft peaks. Then frost the top and sides of the cake with an offset spatula, using minimal strokes to keep the surface smooth. If desired, add shredded coconut on the top and sides of the cake.

Saturday, September 19, 2009

Experiment #3: Pastel de Tres Leches

Pre-Lab

So I’m having a party at my place. YAH. Its been a long time since I’ve hosted a party so of course, I’m going to use the opportunity to try yet another cake recipe from Tartine. Since it’s the tail end of summer (its still too hot in CA to declare it Fall), I’m going to make a refreshing Tres Leches (Three Milk) cake; one of my favorites. Amazingly moist, milky, and sweet and yet I’ve never made it before. So in preparation for my endeavor, I’ve read the recipe and associated recipes for the fillings/cake, etc. and I find it very similar to the Summer Fruit Bavarian cake I made in my first experiment. The differences are that the Tres Leches cake calls for a Chiffon cake base (instead of the génoise I made for the Bavarian cake) and a coconut syrup and optional caramel topping (uh, of COURSE I’m going to do the caramel!). Otherwise, the composition of the cake does consist of a filling made of pastry cream with the gelatin (to firm up the cream) and whip cream (to make it light and airy), just like in the Bavarian cake. This will be a good opportunity for me to practice making the pastry cream again (hopefully with a little more finesse). The cake is also topped with whipped heavy cream, which hopefully turn out better than last time now that I know that less manipulation frosting the cake = better looking cake.

I’m also going to start writing in the weights for some of the ingredients that I’ll be measuring out by weight (in metric units of course; it is the system used most commonly by chemists). At my job, it’s really routine for me to weigh things as a form of measurement. We hardly do anything my volume, except liquids, in which case, we have to usually take into account the density of the material. But solids come in all densities…think light and fluffy marshmallows versus sugar; the same volume of marshmallows will be a lot lighter than the same volume of sugar. Flour is notorious for varying in volume depending on how much air is incorporated into it while measuring; a tightly packed cup of flour can weigh several grams more than a lightly packed cup. So you just can’t measure solids by volume; it just isn’t accurate enough. For some recipes, it doesn’t really matter too much. But others such as one as important as the cake-for-my-party, it does.

One last note about the order of the experiment: since my cake base needs time to cool, I’ll make that first. Then I’ll make the coconut syrup, caramel, pastry cream (which I’ll make into the filling for the cake right away). I’ll let the assembled cake components party in the fridge overnight, then finish the cake with whipped cream and coconut (not in the recipe, but I like coconut and it’ll make it pretty) the morning of my party.