Make-Ahead Sourdough Breakfast Casserole

Equipment

• Cast iron skillet
• Stovetop
• Oven

Ingredients

• 1 Tbsp. olive oil
• ½ lb. ground mild Italian sausage
• 1 cup sliced red onion (from 1 medium onion)
• 1 medium bunch Lacinato kale, stemmed and coarsely chopped (3 packed cups)
• 5 large eggs
• 1 ½ cups half-and-half
• 1 Tbsp. Dijon mustard
• 1 tsp. kosher salt
• 8 oz. day-old sourdough bread loaf, torn into 1-inch pieces (about 6 cups)
• 4 oz. sharp white Cheddar cheese, shredded (about 1 cup)

Instructions

1. 1Warm the olive oil in a 10-inch cast-iron skillet over medium-high heat. Stir in the mild Italian sausage, breaking the meat apart as it cooks until it starts to brown, 4 to 6 minutes.
2. 2Toss in the sliced red onion and cook for about 3 minutes until soft. Stir in the chopped kale and cook for another 2 minutes until the leaves wilt. Take the skillet off the heat and let the mixture cool for 15 minutes.
3. 3Whisk the eggs, half-and-half, Dijon mustard, and kosher salt in a large mixing bowl. Fold in the torn sourdough bread pieces to coat them well. Let the bowl sit for 15 minutes, stirring occasionally, so the bread absorbs the custard and doesn't dry out.
4. 4Transfer the cooled sausage and vegetable mixture into the bowl with the soaked bread. Leave the skillet unwashed so the residual fat prevents sticking. Fold the shredded sharp white cheddar cheese into the bowl, then spoon the entire mixture back into the skillet.
5. 5Press a sheet of plastic wrap directly onto the surface of the casserole. Chill in the refrigerator for at least 4 hours, or up to 12 hours.
6. 6Heat the oven to 325°F and let the uncovered skillet sit at room temperature while the oven preheats. Bake for 40 to 45 minutes until the center sets and the top puffs slightly. Let the casserole cool for 10 minutes before slicing so the custard can firm up.

Recipe Details