Warm House Cozy KitchenPancetta and Gruyère Breakfast Casserole - Warm House Cozy Kitchen

Ingredients

• 4 cups (loosely packed) day-old challah or other egg-enriched bread, cut into 3/4-inch cubes
• 2 tablespoons olive oil, divided
• 1 Medium onion, thinly sliced
• 1/2 teaspoon salt
• 1/4 teaspoon sugar
• 1/2lb pancetta (thickly sliced), diced
• 6 eggs
• 1 1/2 cup whole milk
• 1/2 teaspoon dry mustard
• 1/4 teaspoon freshly grated nutmeg
• 2 teaspoons fresh thyme leaves
• salt and freshly ground pepper
• 1 cup grated Gruyère cheese, from about 4 ounces