Preheat the oven to 400 degrees.
In a large pan, cook the onions and mushrooms for 4 minutes until soft. Add the garlic and cook for 1 more minute.
Add the turkey and cook until no longer pink, 5 minutes.
Add the butter and flour, and cook for 2 minutes. Add the milk slowly and whisk constantly. Cook for 5 minutes until the sauce has thickened - salt and pepper to taste.
Pour the mixture into your baking dish. Top with the shredded cheese, then tater tots.
Bake 30-35 minutes until tater tots are golden brown and crispy.
Allow to cool for 10 minutes before serving. Enjoy!