Melt butter in a medium-size pan. Add flour and stir for 1 or 2 minutes. Gradually add milk stirring constantly, to prevent lumps. Bring to a boil and cook until sauce thickens. Add grated cheese and season with salt, pepper and nutmeg.
Cut spinach in medium-size pieces. Season with salt and pepper. Place spinach on the bottom of a lightly greased baking pan. This can be prepared in individual pans too. With the help of a spoon, make 4 holes on the spinach. Carefully place 1 egg in each hole.
Cover eggs with hot sauce and take to oven to broil until golden.
Optional: Garnish with tomato slices if desired.