Strawberry-rhubarb angel cake

1 package Betty CrockerR 1-step white angel food cake mix
1 1/4 cups cold water
2 teaspoons grated orange peel
2 cups sliced rhubarb
1/2 cup granulated sugar
2 tablespoons orange juice
1 pint (2 cups) strawberries, sliced
Red food color
1 container (15 ounces) ricotta cheese
1/4 cup powdered sugar
2 cups frozen (thawed) reduced-fat whipped topping

1.Move oven rack to lowest position (remove other racks). Preheat oven to 350?F.
2.Beat cake mix, cold water and orange peel in extra-large glass or metal bowl on low speed 30 seconds; beat on medium speed 1 minute. Pour into ungreased 10x4-inch angel food cake pan (tube pan). (Do not use bundt cake pan or 9x3 1/2 inch angel food pan, or batter will overflow.)
3.Bake 37 to 47 minutes or until top is dark golden brown and cracks feel very dry and not sticky. Do not underbake. Immediately turn pan upside down onto heatproof funnel or bottle. Let hang about 2 hours or until cake is completely cool. Run knife around edge; remove from pan.
4.Heat rhubarb, granulated sugar and orange juice in 2-quart saucepan over medium heat 10 minutes, stirring occasionally. Cool 15 minutes. Stir in 1 1/2 cups of the strawberries. Add about 4 drops food color if deeper red color is desired. Refrigerate 1 hour.
5.Beat ricotta cheese and powdered sugar in large bowl on medium speed until fluffy. Fold in whipped topping.
6.Cut cake horizontally to make 3 layers. Spread strawberry-rhubab mixture between layers. Frost side and top of cake with ricotta mixture. Arrange remaining strawberries on top. Refrigerate until serving time. Store covered in refrigerator.