Rhubarb Mousse Cake
 
Make 1 (9-inch square) cake
Ingredients
  • 2 ounces white chocolate, chopped
  • 2 tablespoons unsalted butter, cubed
  • ¼ cup whole milk
  • ½ cup all-purpose flour
  • ½ teaspoon baking powder
  • ⅛ teaspoon salt
  • 1 egg
  • ¼ cup granulated sugar
  • ½ teaspoon vanilla extract
  • Rhubarb-Mascarpone Mousse (recipe follows)
  • Rhubarb Ribbon (recipe follows)
Instructions
  1. Preheat oven to 325º. Line a 9-inch square baking pan with parchment paper, letting excess extend over sides.
  2. In a small saucepan, heat chopped white chocolate, cubed butter, and milk over low heat until chocolate and butter have melted. Keep warm.
  3. In a small bowl, whisk together flour, baking powder, and salt.
  4. In the bowl of a stand mixer fitted with the whisk attachment, beat egg, sugar, and vanilla extract at medium speed until tripled in volume and pale in color. (If you lift the whisk and draw an 8 on the top of the batter, you should be able to see the whole 8 before it disappears.) Add flour mixture, and beat at low speed until combined. Add melted white chocolate mixture, and beat until smooth. Pour batter into prepared pan.
  5. Bake until a wooden pick inserted in the center comes out clean, 15 to 20 minutes. Let cool in pan for 10 minutes; using excess parchment as handles, gently remove from pan. Still on parchment, let cool completely on a wire rack. Place a paper towel over top of cake and lightly spray outside edges of parchment with cooking spray before returning cake, still on parchment, to pan.
  6. Pour Rhubarb-Mascarpone Mousse over prepared cake, and smooth top; tap pan gently on counter to remove any large air bubbles. Refrigerate until set, at least 2 hours.
  7. Using excess parchment as handles, transfer from pan to a work surface. Using a serrated knife, slice into 4x1½-inch bars. Top each with a piece of Rhubarb Ribbon, and serve immediately. Store, covered, in refrigerator.
Recipe by Victoria at https://victoriamag.com/rhubarb-mousse-cake-recipe/