In a skillet, cook the ground turkey over medium heat until browned. Drain any excess fat.
Add the chopped onion and minced garlic to the skillet. Cook until the onion is translucent.
In a baking dish, layer the sliced potatoes, ground turkey mixture, and shredded cheddar cheese.
In a small saucepan, melt the butter and stir in the milk. Pour this mixture over the casserole.
Season with salt and black pepper to taste.
Cover the baking dish with aluminum foil and bake for 30 minutes. Remove the foil and bake for an additional 15 minutes, or until the potatoes are tender and the top is golden brown.
Let the casserole cool for a few minutes before serving.
Notes:
Feel free to add other vegetables like bell peppers or carrots for extra flavor and nutrition.