SHORTCRUST PASTRY:

1 1/2 c. all purpose flour
1/2 c. butter, ice cold
1/4 c. shortening, ice cold
1 egg yolk
1/4 c. ice water

FILLING:

1 lg. onion, peeled
1 tbsp. butter
3/4 c. shredded sharp cheddar
3 tbsp. chopped chives
1 whole egg & 1 egg yolk
1/4 c. cream or milk
1 tsp. salt
1/2 tsp. pepper
6 oz. lg. fresh mushrooms

Preheat oven to 400 degrees. Use a pastry cutter or the steel knife of a food processor to combine flour, butter and shortening until mixture resembles coarse cornmeal. Add egg yolk and sprinkle with water. Combine to make a soft dough. Roll out dough on a lightly floured surface. Line a 9" pie or quiche pan with dough. Bake blind in oven until crust is just set, about 15 minutes.

Meanwhile, cut onion until golden. Combine shredded cheese, chives, eggs and milk in a mixing bowl. Season with salt and pepper. Cut stems off mushrooms (and save them for another use). Place whole mushroom caps, stem side up, in the prepared crust.

Place sauteed onions over mushrooms. Pour cheese mixture over all. Return to oven for 15 to 20 minutes, or until mixture is set and brown. Let cool 10 minutes before cutting. Serves 6 to 8.