Meyer Lemon-Olive Oil Chiffon Cake With Berries and Crème Fraiche Bavarian Cream

Ingredients:

For the cake* (see Baker's Notes):

• 1 1/8 cups (157g) Organic Edison flour
• 1 teaspoon baking powder
• 2/3 cup (150g) granulated sugar, plus 2 tablespoons (26g) for the egg whites
• ½ teaspoon kosher salt
• ¼ cup (63g) extra virgin olive oil
• 3 large (63g) egg yolks, at room temperature
• 2 tablespoons (30g) water
• 1 Meyer lemon, zest and juice, divided** (see Baker's Notes).
• 5 large egg whites, at room temperature

For the berry puree:

• 1 pint mixed raspberries and blackberries (or strawberries, if desired)
• 2 teaspoons sugar
• 1 teaspoon lemon juice

For the custard:

• 1 2/3 cup (400g) whole milk
• ½ vanilla bean
• 2 large egg yolks
• 1 whole large egg
• 1/3 cup (80g) sugar
• 1½ tablespoons (15g) Edison flour
• 1½ tablespoons (15g) cornstarch

For the Bavarian cream*** (see Baker's Notes):

• 1 packet (3 teaspoons) gelatin
• 2 tablespoons cold water
• 2 cups custard, divided
• 2 cups heavy cream, very cold
• 1/2 cup crème fraiche
• 1 tablespoon powdered sugar

For the crème fraiche whipped cream: 

• 1 cup heavy whipping cream, very cold
• ¼ cup crème fraiche 
• 2 tablespoons powdered sugar

For decoration:

• Fresh edible flours (optional)
• Fresh blackberries, raspberries, blueberries, strawberries, or a mix (optional)

Instructions:

To make the cake:

1. Prepare an 8-inch springform cake pan by lining the bottom with an 8-inch round piece of parchment paper. Do not butter or line the sides.
2. Preheat the oven to 325°
3. Sift together the flour and the baking powder three times.
4. In a medium-sized mixing bowl, whisk together the sifted flour, 2/3 cup sugar, and salt.
5. In a separate small bowl, whisk together the olive oil and egg yolks very well, until pale and thick. Add the water, lemon juice (reserving ¼ teaspoon of juice for the egg whites), and lemon zest. Stir to combine.
6. Pour the olive oil mixture into the flour mixture and whisk very well until smooth, about 1 minute.
7. Place the egg whites in the bowl of an electric stand mixer (make sure the bowl is very clean and dry). Use the whisk attachment to whisk on medium speed until frothy.
8. Add the reserved ¼ teaspoon of lemon juice and turn the mixer up to medium-high. Whisk until the whites hold soft peaks, then slowly pour in the remaining 2 tablespoons of sugar. Continue to whisk on medium-high speed until the whites hold stiff, glossy peaks.
9. Scoop about 1/3 of the egg whites into the yolk mixture and use a rubber spatula to stir well until combined. Scoop another 1/3 of the egg whites and fold in gently to combine. Scoop the remaining 1/3 of the egg whites and fold in very gently.
10. With a rubber spatula, scrape the batter into the prepared cake pan. Smooth the top so that it is even. Bake for 45-55 minutes, or until a cake tester comes out clean. Do NOT open the oven for the first 35 minutes of baking.
11. Let the cake cool on a wire rack in the pan until it is completely cool. To unmold, run a thin knife around the edge to loosen the cake from the pan.
12. Once the cake is completely cool, trim the cake to make the layers and prepare to assemble. To do so, set the cake on a rotating cake stand if you have one or a cutting board if you don't. Either way, hold a sharp serrated knife completely horizontal. Carefully trim any raised parts from the top so that it is flat. 
13. Score the cake exactly in the middle along the horizontal meridian lightly with the knife. Using this score as a guide, very carefully cut the layer in half horizontally so that you now have two cake layers. Set aside and use within an hour of dividing or wrap tightly and refrigerate for later use.

To make the berry puree:

Puree all ingredients together in a blender until smooth. Store in a sealed container in the refrigerator until ready to use, up to a week.

To make the custard:

This custard will be folded with crème fraiche whipped cream to make the Bavarian cream. You can make it up to 3 days ahead.

1. Pour the milk into a medium saucepan. Slice the vanilla bean pod lengthwise and scrape the beans into the milk. Warm over medium-high heat until bubbles appear around the edges. Stir occasionally while warming.
2. While the milk is heating, in a small bowl whisk together the egg and egg yolks. Add the sugar and whisk together well, until pale and thick.
3. Sift together the flour and the corn starch. Fold into the yolk mixture until just combined.
4. Once the milk has been heated until it starts to bubble at the edges, whisk ½ cup of the hot milk into the egg mixture until well combined. Whisk another ½ cup of the hot milk into the egg mixture, then pour the egg mixture into the saucepan in a slow, steady stream, whisking constantly.
5. Heat over medium heat, whisking constantly (don't stop whisking!!). Bring to a slow bubbling boil and boil for about 1 minute, whisking constantly, until thickened.
6. Remove from the heat and pour into a clean mixing bowl to cool. Cover the surface with plastic wrap while it's cooling. Once it has cooled, store it in the refrigerator.

To make the crème fraiche Bavarian cream:

1. Mix the gelatin and the cold water to dissolve and let sit for about ten minutes.
2. In a bain-marie (a double boiler or a bowl set over, but not touching, a saucepan of simmering water), warm ½ cup of the custard until hot to the touch (you can touch a tiny bit to your wrist using a spatula, should feel hot but not scalding). Remove from the heat.
3. Immediately stir the gelatin into the custard very well until it is all melted together.
4. Whisk half of the remaining cold custard into the warmed custard-gelatin mixture until smooth. Stir the rest of the cold custard in until all smooth.
5. Immediately proceed to make the whipped cream (try not to let the custard sit too long after adding the gelatin). To do so, add the cold cream, crème fraiche, and powdered sugar to the bowl of an electric stand mixer fitted with a whisk attachment. Whisk on medium until it holds soft peaks**** (see Baker's Notes).
6. Stir 1/3 of the whipped cream into the custard, stirring well until smooth and combined. Fold another third in gently, then fold the final third in very gently. Use to fill the cake immediately.

To make crème fraiche whipped cream:

Add the cold cream, crème fraiche, and powdered sugar to the bowl of an electric stand mixer fitted with a whisk attachment. Whisk on medium until it holds soft peaks.

To assemble the cake:

1. Set the bottom cake layer onto a platter or cake board, if you have a cake wrap***** (see Baker's Notes). (If you're using a springform pan instead, prepare it by lining with plastic wrap around the sides and placing the bottom cake layer inside it.)
2. Wrap the cake wrap around the cake layer snugly and secure it with tape or a sticker.
3. Use a pastry brush to brush the top of this cake layer with fruit puree. You want the whole layer covered well but not too soaked.
4. Spoon some of the Bavarian cream onto the cake until you have a layer about 1 inch thick.
5. Cover the layer with a mixture of berries.
6. Spoon Bavarian cream onto the berries, smoothing with the spoon as needed, until they are completely covered.
7. Cover again with another layer of berries.
8. Cover the berries again with the rest of the cream, using the back of the spoon to make sure there aren't any air pockets.
9. Very gently fit the second cake layer on top of the berries and cream.
10. Use the pastry brush to brush the top of the cake with the fruit puree.
11. Cover and let chill for four hours or overnight.
12. To finish, gently spoon the crème fraiche whipped cream onto the top of the cake. Smooth with an offset spatula. Decorate with flowers or berries, or just leave as is.

The cake will keep well in the fridge for up to 3 days. It is best if topped just before serving, but the flowers may keep okay for a few days, depending on how fresh they are.