2 c. sifted all-purpose flour
4 tsp. baking powder
1 tsp. salt
6 tbsp. (3/4 stick) butter
1/2 c. buttermilk

FILLING:

8 med. onions, thinly sliced
6 tbsp. (3/4 stick) butter
4 eggs
1 container (1 pt.) dairy sour cream
1 tsp. salt
1/4 tsp. pepper

Combine flour, baking powder, and salt in a medium sized bowl. Cut in butter with pastry blender until mixture is crumbly. Gradually stir in buttermilk until well blended. Turn out onto a lightly floured surface. Knead until dough is smooth.

Roll dough between 2 sheets of floured wax paper to a 15 inch round. Fit into a 9 inch spring-form pan, pressing firmly against side. Cut top edge of pastry off evenly with top edge of pan. Chill while preparing the filling.

Saute onions in butter in large skillet until tender, about 3 minutes. Cool 5 minutes. Spoon into pastry lined pan. Beat eggs slightly in a medium size bowl. Stir in sour cream, salt, and pepper, blending well. Pour over onions. Bake in very hot oven (450 degrees) for 10 minutes. Lower oven temperature to moderate (350 degrees); bake 45 minutes or until a thin knife inserted comes out clean. Garnish with parsley or cherry tomatoes, if you wish.