Step 1

Heat oven to 350 degrees. Grease and flour two 8-inch round cake pans. In a bowl, sift together flour, baking soda, baking powder, and salt. Set aside.

Step 2

Cream together butter and sugar. Add egg yolks one at a time. In another bowl, mash bananas, and combine with buttermilk and vanilla. Add alternately to butter mixture with flour mixture, beginning and ending with flour.

Step 3

Beat egg whites until stiff; fold into batter.

Step 4

Divide batter between prepared pans. Bake until a toothpick inserted into the center comes out clean, 30 to 35 minutes. Let cool in pans for 5 minutes, then turn out onto a rack to cool completely.

Step 5

When cake layers are cool, whip cream with confectioners' sugar until stiff. Fold in sour cream. Place a cake layer on a plate, and spread with filling to within 1 inch of edge. Place other layer on top, and press down lightly. Chill for 1 hour.

Step 6

Slice bananas 1/2 inch thick. Melt butter in a large saute pan over medium heat. When it sizzles, add slices in a single layer. Sprinkle with sugar. When golden brown, turn slices; cook until brown on other side.

Step 7

Carefully pour in bourbon (using a measuring cup, never the bottle) and ignite with a match. Cook until flames die down, shaking the pan to toss bananas in syrup. Remove from heat.

Step 8

Arrange banana slices on top of cake. Pour remaining syrup over cake, letting it drip down sides. Serve immediately.