01 - 
                Butter a 9×13-inch baking dish. Spread the croissant chunks across the bottom.
              
              
              
                02 - 
                Scatter the browned sausage and grated cheese on top of the croissant pieces.
              
              
              
                03 - 
                In a big bowl, beat the eggs, milk, powdered mustard, salt, and black pepper until everything's blended together.
              
              
              
                04 - 
                Dump the egg mix over everything else, then push down softly so the croissants get nice and wet.
              
              
              
                05 - 
                Wrap the dish with plastic and stick it in the fridge all night or at least 2 hours.
              
              
              
                06 - 
                Heat your oven to 350°F (175°C). Take the dish out and let it warm up while the oven gets hot. Cook it uncovered for 40-45 minutes until it's golden on top and firm in the middle.
              
              
              
                07 - 
                Let it sit for a bit before cutting. Enjoy while it's still warm.