Make Ahead Ham and Veggie Breakfast Sandwiches

Ingredients (11)

• 1/2 tablespoon olive oil, plus more for oiling the pan
• 1/2 large onion, thinly sliced
• 2 cups packed baby spinach
• 10 large eggs
• 2 tablespoons cream or half and half
• 1/2 teaspoon fine sea salt
• 1/4 teaspoon fresh ground black pepper
• 2 tablespoons chopped fresh herbs, like chives, parsley or basil
• 6 slices ham, turkey, bacon or sausage patties, optional
• 6 slices cheese, like cheddar, provolone, or Swiss
• 6 English muffins or bread rolls, try homemade English muffins