4 eggs
2 c. milk
1 tsp. salt
2 c. flour
1 c. grated Cheddar cheese
4 oz. Gruyere

Preheat oven to 425 degrees. Beat eggs with milk, salt and flour until smooth. Grease cups of cast iron popover pan, then preheat pan for 5 minutes. Fold cheese into batter. Spray pan with food release product and fill 3/4 full. Bake 30 to 35 minutes. Serve hot.