Preheat oven to 350F and line a small/medium cookie sheet with parchment paper then set aside.
In a frying pan cook ground sausage until brown throughout. Do not drain. Set heat to medium-low and mix in the ¼ cup flour to the sausage sitting in grease, it should be bubbling. The point here is to create a roux which in the end will result in a thick sausage gravy. Add the 2 tbsp of milk and pepper, remove from heat. If you plan on using that pan for the rest of the steps, pour the sausage gravy into a bowl, set it aside, and clean the pan.
For the bacon, there are multiple ways to cook it, such as: in the air fryer with the basket- it’s mess free and reduces the bacon smell in the house. Stovetop, oven, or microwave bacon. Once bacon is prepared the way you prefer, crumble it and set it aside.
In a frying pan, cook the shredded hash browns until golden crispy on both sides. If using oil to cook them, use olive oil but only add as needed so that the hash browns don’t carry over extra grease or become soggy.
Mix an egg and 2 tbsp heavy cream in a small bowl and set aside.
Now it’s time to assemble the bars. Place one pastry sheet onto the prepared cookie sheet. Spread the sausage gravy into a small square within the pastry sheet so it leaves about an inch of bare pastry around the perimeter. Add the hash browns on top of the sausage gravy.
Carefully pour about ½ of the egg mixture on top of the hash browns, make sure large amounts of the egg mixture don’t pour out onto the bare pastry sheet. Brush the bare pastry perimeter with some of the egg mixture, there should still be a good amount left for the puff pastry sheet that is going to go on top.
Place 4 slices of cheese on top of the layered breakfast. Sprinkle bacon crumbles over the cheese slices and then top with shredded cheese.
Carefully place the second puff pastry sheet on top and press the edges to connect the top and bottom pastry sheets. Press them together with a fork all the way around. Brush egg wash all over the top and bake for 18-23 minutes or until golden brown. Let cool for 5-10 minutes before cutting into 9 pieces, or smaller. Serve while still hot/warm for ultimate flakiness.