Make-Ahead Cheesy Ham-Mushroom Egg Bake

Name: Make-Ahead Cheesy Ham-Mushroom Egg Bake
Prep time: 25 min
Cook time: 35 min
Total time: 1 h
Cuisine: American
Ingredients: 2 1/2 cups shredded cheddar cheese or 2 1/2 cups swiss cheese, divided; 1/4 cup butter; 1/2 lb fresh sliced mushrooms; 1 small chopped yellow onion (or use 6 green onions, chopped); 1 small green bell peppers or 1 small red bell pepper, seeded and chopped; 2 cups fully-cooked cubed ham; 8 large eggs; 1/4 cup all-purpose flour; 1 3/4 cups half-and-half cream or 1 3/4 cups milk; 1/4 teaspoon seasoning salt or 1/4 teaspoon white salt; fresh ground black pepper (to taste)