Step 1

Preheat the oven to 350 degrees F (175 degrees C).

Step 2

Press biscuits into the bottom of a 9x13-inch pan, flattening them out to the edges.

Step 3

Bake in the preheated oven until biscuits begin to rise and crisp, about 10 minutes. Remove from the oven and push the centers of the biscuits down to flatten. Leave oven on.

Step 4

While the biscuits are baking, heat oil in a large skillet over medium heat. Add hash browns, onion salt, garlic salt, salt, and pepper. Cook until golden brown, 5 to 7 minutes. Remove to a plate. Add ham to the same skillet and cook until browned, 3 to 5 minutes. Remove from the heat.

Step 5

Mix condensed soup and 1/2 cup milk in a bowl until combined. Whisk remaining milk with eggs in a separate bowl.

Step 6

Assemble casserole: Pour hash browns over the biscuits, then pour 1/2 of the butter over top. Sprinkle with 1 package of Cheddar cheese, then layer with condensed soup mixture, egg mixture, remaining butter, ham, and remaining package of cheese. Cover with aluminum foil.

Step 7

Bake in the oven for 25 to 30 minutes. Remove foil and cook for an additional 5 to 10 minutes.