2 cups milk
1 teaspoon seasoned salt
1 teaspoon ground black pepper
2 cups shredded cheddar cheese
1 onion, chopped
1 green bell pepper, chopped
3 red potatoes, thinly sliced
Place bacon in a large skillet and cook over medium-high heat, turning occasionally, until evenly browned, about 10 minutes. Drain bacon slices on paper towels, reserving 1 tablespoon bacon grease. Crumble bacon into pieces.
Grease a 9×13 inch casserole dish with reserved bacon grease.
Place milk, eggs, seasoned salt, and black pepper in the bowl of a stand mixer fitted with a paddle attachment. Beat on medium speed until smooth and pale, about 5 minutes.Add bacon pieces, cheddar cheese, onion, and green bell pepper; beat until combined, about 2 minutes more.
Layer potato slices in the bottom of the casserole dish. Pour egg mixture over potatoes. Arrange sliced mushrooms on top. Cover casserole with aluminum foil.
Refrigerate over night. Bake in 350 degrees preheated oven, about 35 minutes. Remove aluminum foil and bake until eggs are set, about 30 minutes more.