Preheat the oven to 400 degrees F. Lightly grease a 9”x5” glass dish.

Cook the bacon strips in a pan over medium high heat. Remove to a plate. Cook the onions in the bacon grease until softened. Remove to the plate.

Whisk the egg, salt, and pepper together in a bowl.

Roll out the puff pastry so it's flat on a surface. Poke some holes in it with a fork so it can vent while cooking. Cut 1/4 of the pastry sheet off the end. Place the longer piece in the glass dish and press the ends up the sides of the dish.

Pour in the eggs. Top with the onions, bacon, and shredded cheese.

Place the small piece of puff pastry across the top and secure it to the outer piece around the edges by pinching it together with your fingers. It doesn’t have to be perfect!

Bake for 30-35 minutes, until the crust no longer looks doughy and is golden brown.