Method:

• Move oven rack to lowest position. Remove other racks. Heat oven to 350°F (180°C). In an extra-large glass or metal bowl, beat cake mix, water and orange peel with electric mixer on low speed 30 seconds; beat on medium speed 1 minute. Pour into ungreased 10-inch (25 cm) angel food (tube) cake pan. (Do not use fluted tube cake pan or 9-inch (23 cm) angel food pan as batter will overflow.)
• 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 glass bottle until cake is completely cool, about 2 hours.
• Meanwhile, in 2-qt (2 L) saucepan, mix rhubarb, 1/2 cup (125 mL) granulated sugar and the orange juice. Cook over medium heat 10 minutes, stirring occasionally. Cool 15 minutes. Stir in 1 1/2 cup (375 mL) strawberries. Stir in 4 drops food colouring if deeper red colour is desired. Refrigerate about 1 hour.
• In chilled medium bowl, beat whipping cream and 3 tbsp (45 mL) icing sugar on high speed until soft peaks form. In large bowl, beat ricotta cheese and 1/4 cup (50 mL) icing sugar on medium speed until fluffy. Fold in whipping cream.
• Run knife around edges of cake; remove from pan. Cut cake horizontally to make three layers. Spread filling evenly on top of two cake layers. Stack layers. Frost side and top of cake with frosting. Arrange 1/2 cup (125 mL) strawberries over top of cake. Store covered in refrigerator.