1. Preheat oven to 350°. Lightly grease and flour 2 (8-inch) round cake pans. Heat milk in a small saucepan over medium heat. Add saffron and zest. Bring just to a simmer; remove from heat, and set aside.
2. Sift together flour, baking powder, and baking soda in a large bowl. Stir in salt.
3. Beat together butter and almond paste at medium speed in the bowl of an electric mixer fitted with a paddle attachment about 3 minutes or until creamy. Gradually add powdered sugar, and beat until fluffy, scraping down sides. Add eggs, 1 at a time, beating just until blended after each addition. Gradually add flour mixture alternately with sour cream, beginning and ending with flour mixture and beating at medium speed just until blended after each addition. Add reserved milk mixture; beat just until blended. Do not overmix.
4. Pour batter into prepared pans. Shake pans gently, or use a spatula to smooth tops. Bake at 350° for 25 to 30 minutes or until a wooden pick inserted in center of cake comes out clean. Let cool in pans on wire racks 5 minutes. Remove from pans, and serve warm, dusted with more powdered sugar or drizzled with orange juice combined with 2 to 3 tablespoons powdered sugar, if desired.
*Stir flour before measuring.
**Do not use marzipan, which contains added sugar.