05Add the onion, salt, and pepper, and cook until soft, about 4 minutes, stirring occasionally with a large wooden spoon.06Incorporate the ham and cook, stirring, for 2 minutes.07Add the flour and cook, stirring constantly, for 2 minutes.08Pour in the milk and bring to a boil, stirring frequently. Reduce the heat to medium-low and simmer, stirring occasionally, for 2 minutes, or until thickened.09Using the mitts or pot holders, remove the saucepan from the heat and add 2 cups of the cheese. Stir until thoroughly combined.10Pour the milk mixture over the Tater Tots and sprinkle with the remaining 1 cup of cheese.11Bake in the oven until bubbly and golden brown, about 35 minutes.12Using the mitts or pot holders, remove from the oven and let rest for 5 minutes before serving.