- Preheat oven to 350° F.
- Grease or line a loaf pan completely with foil (no need to grease foil).
- On wax paper, sift flour, baking powder & salt. Set aside.
- Place egg whites in a medium bowl, yolks in a large bowl.
- With an electric hand mixer on high, beat egg whites until they form stiff peaks. Set aside.
- To the egg yolks add oil, sugar & vanilla. Beat on high speed for about a minute until thick.
- With beater on low speed, slowly add milk, then slowly add flour mixture.
- Using a spatula, gently fold egg whites into flour mixture.
- Place about 2/3 cup of the batter into the empty egg white bowl. Fold in cocoa powder and 2 Tbsp. sugar.
- Spoon alternating layers into the pan. For the swirl, run a dull knife through the batter 3 or 4 times, lengthwise.
- Bake for 45 minutes or until a toothpick inserted in the center comes out clean. Cool in the pan at least 10 minutes. Store tightly wrapped.