Preheat oven to 425°F. Combine 1-1/2 C flour with caraway seed and salt. Cut in 1/2 C butter until mixture is like coarse meal. Gradually add water to make dough. Turn onto floured surface, roll and fit in 10" tart pan. Prick with fork; bake at 425°F for 10 minutes. Reduce oven heat to 375°F. Melt 1/4 C butter in skillet; sauté onion until lightly browned. Spoon into pastry shell. Combine eggs, sour cream, milk, and flour; blend well. Spoon over onion. Bake at 375°F for 30 minutes or until knife inserted in center comes out clean. Garnish with bacon.