Combine flour, salt, and baking powder in a large bowl. Add cold butter and mix until it resembles coarse crumbs. Stir in shredded cheese. In a separate bowl, whisk together egg and cold water, then gradually add to the flour mixture until a dough forms. Roll out the dough into rectangles.

Mix together cooked sausage or bacon, scrambled eggs, green onions, garlic powder, and onion powder in a bowl for the filling.

Cut rolled-out dough into smaller rectangles, place half on a baking sheet, spoon filling onto each, top with another rectangle, seal edges, and crimp with a fork.

Brush tops with beaten egg, preheat oven to 375°F, and bake for 20-25 minutes until golden brown. Let cool slightly before serving.