Berries-and-Cream Bars

Ingredients

• 2 cups all-purpose flour
• 1.5 teaspoons baking powder
• 0.75 teaspoons sea salt
• 10 tablespoons unsalted butter , at room temperature
• 3 tablespoons vegetable oil
• 1 cup sugar
• 3 large egg whites
• 1 teaspoon vanilla extract
• 0.25 teaspoons almond extract
• 0.67 cups whole milk , at room temperature
• 0.5 cups mixed berry jam or preserves , divided

Instructions

1. 1

   Preheat the oven to 350 degrees F (175 degrees C) and position rack in center. Lightly grease bottom of a 9-inch square cake pan. Line bottom with parchment paper. Grease and lightly flour parchment and sides of pan.

2. 2

   Whisk flour, baking powder, and salt together in a medium bowl.

3. 3

   Mix butter and oil in the bowl of a stand mixer fitted with a paddle attachment at medium speed until well combined, about 1 minute. Mix in sugar at medium-high speed until light and fluffy, 4 to 5 minutes. Mix in egg whites in 2 or 3 additions at medium speed until well combined, scraping bowl well after each addition. Mix in 1 teaspoon vanilla and the almond extract.

4. 4

   Mix in about 1/3 of flour mixture at low speed. Mix in 1/3 cup milk; scrape bowl well. Repeat, alternating flour mixture and milk, until fully incorporated and batter is smooth.

5. 5

   Spread batter in an even layer in prepared pan. Bake until a toothpick inserted into center comes out clean or with a few moist crumbs, about 30 minutes.

6. 6

   Let cool in pan 10 minutes, then run an offset spatula or a knife around edge of cake and invert onto a wire rack. Remove parchment and let cool completely.

7. 7

   Using a large serrated knife, halve cake horizontally to make two layers. Transfer one layer, cut side up, to a platter. Top with 1/2 cup jam, spreading evenly. Top with second cake layer, cut-side down.

8. 8

   Meanwhile, make berry cream: puree 2/3 cup jam in a blender or mini food processor until very smooth.

9. 9

   Beat cream in the bowl of a stand mixer fitted with a whisk attachment at medium speed until it begins to thicken, about 1 minute. Mix in marshmallow creme at medium-high speed until soft peaks form. Mix in puréed jam and 1 teaspoon vanilla at low speed until well combined. (If needed, fold whipped cream by hand to more evenly incorporate jam.) Frost top and sides of cake with berry cream.

10. 10

    For garnish, crush freeze-dried berries with a mortar and pestle (or your hands) into a mixture of small pieces and powder; sprinkle over cake. Cut cake into 12 pieces. Chill in an airtight container until ready to serve, up to 2 days.