Citrus Angel Food Cake

Into bowl, sift together 1/4 cup (50 mL) of the flour and 3/4 cup (175 ml) of the sugar; sift again. Set aside.

In large mixing bowl (not plastic), beat egg whites until foamy. Add lemon juice, cream of tartar and salt ; beat until soft peaks form. Gradually add remaining sugar, 2 tbsp (25 ml) at a time, beating until mixture is glossy and stiff peaks form.

A quarter at a time, sift flour mixture over egg whites, gently folding in each addition until well blended. Gently fold in vanilla and lemon and lime rinds. Pour into ungreased 10-inch (4 L) tube pan.

Run spatula through batter to eliminate any large air pockets. Smooth top with spatula. Bake in 350°F (180°C) oven for 40 to 45 minutes or until cake springs back when lightly touched.

Turn pan upside down and let hang on legs attached to pan or on inverted funnel, or bottle, until completely cool. Remove from pan. (Cake can be stored in airtight container for up to 2 days or frozen for up to 1 month.)

Orange Yogurt Sauce: Line plastic sieve with cheesecloth; set over bowl. Spoon in yogurt; cover and let drain in refrigerator for at least 12 hours or until thick. Discard liquid. Whisk together drained yogurt, orange juice, sugar, orange rind and juice concentrate. Pour sauce over each serving.

Garnish: Garnish with orange segments.