To prepare cake: Preheat oven to 350 degrees F. Line the bottom of a 9-by-13-inch baking pan with parchment paper; coat the paper and sides of the pan with cooking spray.

Beat granulated sugar, oil and butter in a large mixing bowl with an electric mixer on medium speed until well combined. Beat in eggs, one at a time, until just incorporated.

Whisk whole-wheat (or all-purpose) flour, cake flour, baking powder, baking soda and salt in a medium bowl. Combine buttermilk, lemon zest, lemon juice, 2 teaspoons vanilla and almond extract in a measuring cup. With the mixer on low speed, add the dry ingredients to the mixing bowl alternately with the buttermilk mixture, beating just until incorporated after each addition, scraping down the sides as necessary. Spread the batter in the prepared pan.

Bake until a toothpick inserted in the center comes out clean, 28 to 34 minutes. Let cool in the pan on a wire rack for 15 minutes. Turn out onto the rack and let cool completely, about 1 hour.

To prepare frosting: Beat cream cheese, 1/2 cup confectioners' sugar, yogurt and 1/2 teaspoon vanilla in a mixing bowl until smooth.

To decorate: Invert the cake onto a platter. Spread the frosting over the top and sides. Use raspberries and blueberries to make flowers all over the top of the cake, leaving a little space between each flower. If using blueberries for the center of the flowers, stack two on top of each other and stick together with a little bit of frosting. Place strawberries slices all around the edge of the cake with the pointed ends up.