Overnight Asparagus Mushroom Strata

Ingredients (12)

• + 2 teaspoons butter, or as needed add to pantry
• + 1 ¾ cups sliced crimini mushrooms add to pantry
• + 5 English muffins, split and toasted add to pantry
• + 1 cup shredded Colby-Monterey Jack cheese add to pantry
• + 1 pound fresh asparagus, trimmed and cut into 1-inch pieces add to pantry
• + ½ cup chopped red bell pepper add to pantry
• ✓ ½ onion, finely chopped
• ✓ 8 eggs
• + 2 cups milk add to pantry
• + 1 teaspoon salt add to pantry
• + 1 teaspoon dry mustard powder add to pantry
• ✓ ¼ teaspoon ground black pepper