Oven 325F. Postition a rack in the center of the oven. Grease a 9 1/2 x 4" Bundt or fluted tube pan, greasing well. Mix cinnamon with 3 tbs. sugar. Sift flour, baking powder, soda into a bowl. In another bowl, mix sour cream, yogurt and vanilla. In large bowl, beat oil with 1 cup sugar and 1 egg until smooth and fluffy. Beat in second egg. At low speed, stir in flour mixture alternately with the sour cream mixtures, each in 2 portions. In another large bowl, whip egg whites until soft peaks form. Beat in remaining 2 tbs. sugar and whip until shiny but not dry. Fold in batter until just blended. Pour about 1/3 of the batter into the prepared pan. Sprinkle with half the cinnamon mixture. Gently spoon another third of the batter in dollops over the mixture. Sprinkle with remaining cinnamon mixture. Gently spoon the remaining batter in dollops over it. Spread gently to cover the cinnamon mixture. Bake about 60 minutes or until cake tester comes out clean. Cool in pan 15 minutes. Run a thin-bladed flexible knife around the center tube, but not around sides of pan. Invert the cake onto a rack and cool completely. (Cake can be kept, wrapped, up to 2 days at room temp. or 3 days in refrig.) Serve at room temperature. Posted to Eat-L by bill spalding. Per serving: 272 Calories; 8g Fat (28% calories from fat); 6g Protein; 43g Carbohydrate; 40mg Cholesterol; 185mg Sodium Recipe by: Palm Beach Post, 10/10/91 Posted to EAT-LF Digest by Betsy Burtis on Feb 4, 98