Peel and slice the potatoes.

Preheat the oven to 350°F. Lightly grease an 8x8” casserole dish.

In a skillet over medium heat, brown the ground beef with the onion, crumbling it as it cooks. Drain any excess fat. Add the garlic and cook for 1 minute. Remove from pan and set aside.

In the same skillet, melt the butter. Whisk in the flour. Cook that for a minute to get the raw flour taste out, then whisk in the milk, salt and pepper.

Layer half the potatoes, half the meat, half the sauce, and half the cheese. Repeat the layers.

Cover with aluminum foil and bake for 1 hour. Remove the foil and bake for an additional 15-20 minutes, until the potatoes are tender and the cheese is bubbly.