Preheat your oven to 375°F (190°C).
Peel and slice potatoes thinly and evenly.
In a skillet, melt butter and sauté onion, garlic, and thyme.
Add beef and cook until browned. Season well.
Sprinkle flour, stir to coat, and cook for 1 minute.
Gradually stir in broth and milk until thickened.
Butter a 9"x13" dish or use non-stick spray.
Layer half potatoes, half beef mixture, then repeat.
Cover with foil and bake for 45 minutes.
Uncover, top with cheese, and bake 10–15 mins more.
Let it rest for 10–15 minutes before serving. Garnish if desired.
