(Dutch-process or American-style) Preheat oven to 350 degrees. Coat a 12-cup tube pan with nonstick cooking spray. If pan does not have removable bottom, insert a ring of wax paper cut to fit pan bottom. Dust pan with flour, tapping out excess. In a small heavy saucepan, melt butter over medium heat; cook gently until butter is just nutty brown, 3 to 5 minutes. Immediately remove from burner. Transfer butter to a small metal bowl and add oil. Freeze butter-oil mixture until firm but not hard, about 15 minutes. Sift together flour, baking powder and salt onto wax paper. In a large mixing bowl, combine the butter-oil mixture, sugar, whole egg and egg whites; beat with an electric mixer on medium speed until very light and well blended, about 4 minutes. Blend in vanilla and almond extracts. With the mixer on low speed, beat in half of the dry ingredients just until incorporated. Beat in yogurt and milk, then remaining dry ingredients just until smoothly incorporated; do not overbeat. Place cocoa in a medium-sized bowl. Pour 3 Tbsp. very hot water over cocoa, stirring until completely smooth.. Measure out 1-1/4 cups cake batter. Slowly stir butter into pan. Spoon cocoa batter over vanilla batter, forming pools on surface. Top with pools of remaining vanilla batter. Rum a table knife deeply through batters to create marbling. Rap pan sharply on counter several times to eliminate air pockets produced by marbling. Bake for 50 to 65 minutes, or until a toothpick inserted in the thickest part comes out clean and top springs back when lightly pressed. Transfer pan to wire rack and let stand until cake is cool. Run a knife around pan sides and around center tube to loosen cake. Transfer to a cake plate. Serves 16. The "sour cream" in this recipe is actually nonfat yogurt. Like moistness and helps to tenderize, but unlike sour cream it contributes no fat. 258 calories per serving: 7 grams fat; 120 mg sodium; 25 mg cholesterol.