Ingredients:
- 10 cups cubed stale bread (about 10-12 slices) — 10 cups / 250 g (day-old French bread, challah, or sandwich bread)
- 10 large eggs
- 3 cups whole milk — 3 cups / 720 ml (or 2 cups milk + 1 cup half-and-half for richer custard)
- 1 tsp kosher salt — 1 tsp / 6 g
- 1/2 tsp black pepper — 1/2 tsp / 1 g
- 1/2 tsp dry mustard (optional) — 1/2 tsp / 1 g
- 1/4 tsp hot sauce (optional) — 1/4 tsp / 1 ml
- 8 oz cooked breakfast sausage, crumbled, or cooked bacon, chopped — 8 oz / 225 g (about 2 cups cooked)
- 2 cups shredded sharp cheddar cheese — 2 cups / 200 g (about 8 oz / 225 g)
- 1 small yellow onion, finely chopped and sautéed until translucent — 1 small / ~100 g
- 1/2 cup diced bell pepper, sautéed (optional) — 1/2 cup / 75 g
- 2 tbsp chopped fresh parsley or chives (optional garnish) — 2 tbsp / 6 g
- 1-2 tbsp unsalted butter or neutral oil for greasing — 1-2 tbsp / 15-30 ml
Instructions:
- Prepare bread: Cube bread into 1-inch pieces. If using fresh bread, dry cubes in a 300°F/150°C oven 8-12 minutes until slightly firm.
- Cook add-ins: Cook sausage or bacon until done; drain. Sauté onion and bell pepper until softened. Cool add-ins slightly before assembling.
- Grease and layer: Butter or oil a 9x13-inch (23x33 cm) baking dish. Spread half the bread cubes in an even layer. Sprinkle half the cooked meat/veg and half the cheese. Repeat to create two layers.
- Make custard: In a large bowl, whisk together eggs, milk (or milk + half-and-half), kosher salt, black pepper, dry mustard (if using), and hot sauce (if using) until blended.
- Pour and press: Pour the custard evenly over the layered bread, pressing gently so bread absorbs the liquid. Ensure most pieces are moistened but not floating.
- Cover and chill: Cover tightly with plastic wrap or foil and refrigerate 8-12 hours (overnight). For a quick version, refrigerate at least 2 hours.
- Preheat and bake: Preheat oven to 350°F / 175°C. Remove cover and let sit at room temperature 10-15 minutes while oven heats. Bake on middle rack 45-55 minutes until puffed, golden, and custard is set. Target internal temperature 165°F / 74°C.
- Rest and serve: Let the casserole rest 10-15 minutes before cutting to finish setting the custard. Garnish with chopped parsley or chives and serve warm.