This is really easy if you have leftover mashed potatoes. If not you can always make some.
Fresh spinach (cut up fairly small)
Cheese (2 to 4 oz, cubed)
Preheat oven to 350.
Brown the meat with Worcestershire sauce, onion powder, garlic powder, salt, and pepper. Drain off most, but not all, of the grease. Add about 2 tablespoons flour and mix until the flour is no longer visible. Pour in milk, about half as deep as your meat. Stir. Add spinach. Bring to a simmer. Stir and turn off heat.
Butter a casserole dish or glass pan. Spread in mashed potatoes. Pour in meat mixture. Top with cheese. Cover and bake for about 30 minutes.