Red Grapefruit Chiffon Cake

In large bowl, sift together flour, 3/4 cup (175 mL) of the sugar, baking powder and salt. In separate bowl, whisk together egg yolks, grapefruit rind, grapefruit juice and oil; pour over flour mixture and whisk just until smooth. Set aside.

In large bowl, beat egg whites until foamy; beat in cream of tartar until soft peaks form. Beat in remaining sugar, 2 tbsp (25 mL) at a time, until stiff peaks form; fold one-quarter into batter. Fold in remaining whites. Scrape into 10-inch (4 L) tube pan. Run spatula through batter to eliminate any air bubbles; smooth top.

Bake in bottom third of 350°F (180°C) oven for about 40 minutes or until cake springs back when lightly touched. Turn pan upside down and let cake hang on legs attached to pan, or on bottle, until completely cooled.

Run knife around inside of pan and tube. (Make-ahead: Invert into plastic wrap–lined airtight container; fold plastic wrap over cake. Cover and store for up to 2 days or freeze for up to 2 weeks.) Turn out, bottom side up, onto cake plate.

Icing: In bowl, whisk sugar with grapefruit juice, adding up to 1 tbsp (15 mL) more juice, 1 tsp (5 mL) at a time, if too thick to spoon. Spoon over top of cake, letting excess run down sides.