Two Fat Cats Lemon Zucchini Whoopie Pies With Blueberry Filling
Ingredients
Cakes:
- 4 cups all-purpose flour
- 2 teaspoons baking soda
- 2 teaspoons baking powder
- 1 teaspoon sea salt
- 8 tablespoons unsalted butter, at room temperature
- 1 cup granulated sugar
- 1 cup brown sugar
- 6 tablespoons oil
- 2 large eggs
- ¾ cup whole milk
- 6 ounces shredded zucchini
- 4 teaspoons grated lemon zest
Filling:
- 12 ounces fresh Maine blueberries
- ½ cup granulated sugar
- 2 tablespoons cornstarch
- 2 teaspoons lemon juice
Buttercream meringue:
- 4 large egg whites
- ¼ teaspoon cream of tartar
- 1 1⁄3 cups granulated sugar
- 1⁄3 cup water
- 1 pound unsalted butter
- 2 teaspoons vanilla extract
- A pinch of sea salt
- Confectioners’ sugar (optional)
Instructions
Cakes:
- To make the cakes, preheat the oven to 350°F. Grease two baking sheets, or line them with parchment.
- In a large bowl, whisk together the flour, baking soda, baking powder, and sea salt.
- In the bowl of a stand mixer, beat together the butter, granulated sugar, brown sugar, and oil. Beat in the eggs.
- Add the dry ingredients and the milk alternatively to the butter mixture in three additions, beginning and ending with the dry ingredients. Beat well.
- Stir in the shredded zucchini and lemon zest.
- Using a 2-ounce scoop, place six mounds of batter on each cookie sheet, leaving 2 inches between mounds. This will use half the batter.
- Bake the cakes for 15 to 20 minutes, rotating the pans once. The cakes are done when they are dry and spring back when you press them lightly with your finger.
- Remove them from the oven, transfer to a cooling rack, and then repeat steps 6 and 7 with the remaining batter.
Filling:
- Place the blueberries, sugar, cornstarch, and lemon juice in a medium-sized saucepan. Cook over medium heat until the sugar dissolves and the mixture bubbles. Stir constantly until thickened, resembling the texture of jam. Remove from the heat and set aside.
Buttercream meringue:
- Place the egg whites in the clean, grease-free bowl of your stand mixer. Add the cream of tartar and beat with a whisk attachment on high until the whites hold soft peaks. Slowly add 1⁄3 cup of the granulated sugar and beat until the whites are fairly stiff, but not dry.
- Meanwhile, place the remaining 1 cup sugar and water in a small saucepan, and bring to a boil over medium-high heat. Cook the syrup until the temperature registers 242°F on an instant thermometer. The syrup will be glossy and slightly viscous, with bubbles forming and popping.
- Immediately remove the sugar from the heat and pour about ¼ cup of it into the meringue. Turn the mixer on to high and continue to pour the syrup into the meringue in a slow steady stream, taking care not to hit the whisk attachment.
- When all the syrup is incorporated, continue to beat the meringue on high until it is cool to the touch.
- With the mixer going, add the soft butter in large spoonfuls, beating until smooth after each addition. When all the butter is added, continue to beat until the buttercream is silky smooth. Beat in the vanilla extract. If at any time the buttercream gets soupy or separates, just keep beating. It will eventually come together and your stand mixer will have earned its keep.
- Stir the cooled blueberry compote into the buttercream. You don’t have to add all of it, and you don’t need to mix it thoroughly—a few dark streaks makes a pretty filling.
Assembly
- Place about 3 to 4 ounces of Buttercream Filling on the flat surface of one cake. Top with another cake, rounded side up. Press down on the top cake so that the filling spreads to the edges. Repeat with the rest of the cakes.
- Serve on a platter, and dust the whoopie pies with confectioners’ sugar, if desired.