Preheat oven to 375. Roll out pastry dough just like you would for a pie; however, try to keep it more square or rectangle in shape. Using a pizza cutter, cut your dough into rectangles.
Mix together 2 eggs and 1 egg yolk, reserving the egg white, cheese and "bacon" bits for filling. For the "bacon" bits, sauté about 1/2 C diced mushrooms with olive oil, bacon salt and pepper. Then toss in the egg mixture and cook just until it's not too runny.
On half of the rectangles, add 2-3 tablespoons of your filling. Use a little water on your finger to dampen the outer edge of the piece with the filing and then place your second piece of dough on top. Gently press the edges together with your fingers. Use the tines to crimp it shut.
Combine the egg white with a teaspoon of water. Brush the egg wash on the tops of your unbaked pastries. Transfer to a baking sheet line with parchment. Bake for 10 minutes or until lightly brown. Transfer to a cooling rack. Serve with ketchup or sour cream, if desired.