01 -
Butter a 9x13-inch baking dish. Spread the bread cubes in the dish and set it aside while you cook the sausage.
02 -
Cook the sausage in a large skillet over medium heat for 7-9 minutes, breaking it into small crumbles, until browned and cooked through. Transfer to a paper towel-lined plate if there is excess grease.
03 -
Add the onion and bell pepper to the skillet and cook for 3-4 minutes, just until softened. Let the sausage and vegetables cool for 5 minutes.
04 -
Whisk the eggs, milk, Dijon mustard, salt, pepper, and garlic powder in a large bowl until smooth and evenly blended.
05 -
Scatter the sausage, onion, and bell pepper over the bread. Add the cheddar and Monterey Jack, then pour the egg custard evenly over the top. Press the bread down gently so it soaks.
06 -
Cover the dish tightly and refrigerate for at least 8 hours or up to 24 hours.
07 -
Heat the oven to 350°F (175°C). Uncover the casserole and bake for 50-60 minutes, until puffed, golden, and set in the center. The egg mixture should reach 160°F.
08 -
Let the casserole rest for 10 minutes. Sprinkle with parsley, then slice into squares and serve warm.