Tart rhubarb and fresh strawberries come together for a delicious combination in this classic fluffy cake.
- Move oven rack to lowest position and remove other racks.
- Preheat oven to 350 degrees.
- In an extra-large glass or metal bowl, beat cake mix, water and orange peel with electric mixer on low speed for 30 seconds, then beat on medium speed for 1 minute.
- Pour into an ungreased 10-inch tube cake pan. Bake for 37 to 47 minutes or until top is dark golden brown and cracks feel very dry, not sticky.
- Immediately after removing from oven, turn cake pan upside down onto a glass bottle until cake is completely cool, about 2 hours.
- Meanwhile, in a 2-quart saucepan, mix rhubarb, ½ cup sugar and orange juice. (If using frozen rhubarb, thaw and drain first.) Cook over medium heat 10 minutes, stirring occasionally. Cool for 15 minutes.
- Pour cooled mixture into a container with a lid, and stir in 1 ½ cups strawberries. Refrigerate about 1 hour.
- In chilled medium-sized bowl, beat whipping cream and 3 tablespoons sugar on high speed until soft peaks form. In a large bowl, beat ricotta and powdered sugar on medium speed until fluffy. Fold in whipped cream.
- Run a knife around the edges of the cake and remove from pan. Cut cake horizontally to make three layers.
- Spread filling onto layers, then frost the sides and top of cake. Decorate with remaining ½ cup of strawberries. Store covered in refrigerator until ready to serve.