Italian Bistro Tart

1/2 package frozen puff pastry (1 sheet), thawed
5 yellow onions, thinly sliced
2 tablespoons butter
1/2 pound bacon, cooked
1 egg
3/4 cup whipping cream
1 teaspoon garlic salt
1/2 cup shredded cheddar cheese

Roll pastry to fit an ungreased 10-inch pie pan; flute edges. Pierce crust with fork. Bake at 350 degrees for 15 minutes. Remove from oven and let cool. Cook onions in butter over low heat until soft and tender. Do not brown the onions. Spread crumbled bacon and onions in crust. In a bowl, beat egg, cream and garlic salt. Pour over onion mixture. Sprinkle with cheese.

Bake at 350 degrees for 25 minutes or until set. Let stand 5 minutes before cutting.