To prepare a tater tot and bacon breakfast casserole recipe, you will first need to prepare the ingredients for the casserole. You will need the following ingredients: 2 tbsp. butter, 1/2 cup shredded cheddar cheese, 1 cup chopped scallions, 2 tablespoons mayonnaise, and 1 teaspoon kosher salt. To make the topping, mix together the ketchup, brown sugar, eggs, milk, salt and pepper. Pour the mixture into the bottom of an 8 x8-inch casserole dish. Bake for 35 to 40 minutes, or until the top is brown and bubbly. Remove from the oven and let stand for 5 minutes before serving.