breakfast bread pudding

1 tablespoon olive oil   
1 yellow onion, minced
1 pound bulk breakfast sausage, crumbled
10 eggs   
3 cups milk   
1 teaspoon kosher salt   
1/2 teaspoon freshly ground black pepper   
1/2 teaspoon garlic powder   
1 loaf day old brioche or country white bread, cut into 1 1/2-inch cubes (about 12 cups)
2 cups shredded sharp cheddar cheese (about 8 ounces)

1. heat the olive oil in a mediums skillet over medium-high heat.  add the onions and saute until translucent (about 7 minutes).
2. add the sausage to the skillet and brown, stirring to break up any large clumps.
3. using a slotted spoon, transfer the sausage and onions to a shallow bowl and allow to cool to room temperature.
4. in a large bowl, whisk the eggs, milk, salt, pepper and garlic powder.  stir in the bread, sausage and onion mixture, and the cheese.
5. butter a 13 X 9 inch baking dish, pour mixture into prepared baking dish and cover with foil.  let the dish sit in the refrigerator for at least 1 hour or overnight.
6. preheat the oven to 350.
7. bake the pudding, still covered, for about 45 minutes.  remove the foil and bake 10 to 15 minutes more, until browned.  serve immediately.