Sauté onion in margarine until tender.

Add mushrooms and cook for 10 minutes.

Add salt and pepper. Stir in flour and mix until smooth.

Gradually add water and cook over low heat, stirring continuously, until thickened. Cool.

Roll flaky dough to 1/8-inch thickness. Cut into three-inch rounds.

Place a heaping teaspoonful of mushroom filling in center of each round. Fold dough over filling and press edges with tines of fork.

Place on baking sheet. Brush with egg, sprinkle with sesame seeds. Bake at 425 degrees for 15 minutes. Reduce heat to 375 degrees and bake for another 10 minutes or until golden.