Sift flour; sift again with 1/2 cup/125 mL of the granulated sugar. Sift mixture 1 more time.

In bowl or stand mixer, beat egg whites until foamy. Add cream of tartar, cardamom and salt; beat until soft peaks form. Beat in remaining sugar, 2 tbsp/30 mL at a time, until stiff glossy peaks form.

Sift flour mixture over top in 3 additions, gently folding in each addition until blended. Fold in almonds and almond extract. Pour into ungreased 10-inch/25 cm tube pan. Run spatula through batter to eliminate any large air bubbles; smooth top.

Bake in centre of 350°F/180°C oven until cake springs back when touched lightly, 45 to 50 minutes. Cool upside down on rack.

Orange Custard: In small bowl and using fork, rub sugar and orange rind together, pressing firmly with fork tines to extract oils from rind.

In large bowl and using wooden spoon, beat sugar mixture into egg yolks until smooth and thick. Beat in cornstarch and 1/3 cup/75 mL of the milk.

Meanwhile, in heavy-bottomed saucepan, heat remaining milk over medium heat just until bubbles form around edge. While stirring yolk mixture, slowly add hot milk to bowl; continue beating until thoroughly mixed.

Return mixture to saucepan; cook, stirring, until thick enough to mound on spoon, 3 to 5 minutes. Strain through fine sieve into clean bowl; stir in orange blossom water, if using. Place plastic wrap directly on surface. Refrigerate until cold, about 4 hours.

Before serving, sprinkle cake with a light dusting of icing sugar. Serve with Orange Custard.

Makes 12 servings.