This light-as-air angel food cake from Newman's Own Organics's president Nell Newman was a favorite treat of her father, actor Paul Newman. Added bonus: It's low in fat and easy to make -- the trick is to prepare all the ingredients in advance.
Preheat oven to 350 degrees.
Sift flour together with 1/4 cup sugar and salt 3 times; set aside.
In the bowl of an electric mixer fitted with the whisk attachment, beat egg whites until frothy; add lemon juice and continue beating until soft peaks form, about 4 minutes. Add remaining 1 cup sugar, 1/4 cup at a time, continuing to mix on medium speed until combined and stiff, glossy peaks form, about 5 minutes more.
Sift 1/4 cup of the flour mixture into bowl of egg whites. Using a clean hand, gently fold to combine. Add vanilla and orange zest. Add remaining flour mixture, alternating with chocolate and continuing to gently fold with your hand, until all the flour mixture and chocolate have been added.
Pour batter into a 9 1/2-inch tube pan; drag a knife through batter to remove any air bubbles. Transfer to oven and bake until lightly browned and a knife inserted into the center comes out clean, about 45 minutes. Remove from oven and invert pan; let cool 30 to 45 minutes. Run a knife around the edges and center of tube and invert to remove from pan. Serve with strawberries or whipped cream, as desired.