How to Make It
Heat oil in a large nonstick skillet over medium-high. Add sausage and onion; cook, stirring often, until sausage is browned and onion is tender, 6 to 8 minutes. Stir in kale, and cook until wilted, about 1 minute. Remove from heat, and let cool 5 minutes.
Whisk together milk, mustard, salt, pepper, and eggs in a large bowl.
Combine bread cubes and sausage mixture in a 9x13-inch baking dish coated with cooking spray. Pour milk mixture evenly over bread mixture, pressing gently to submerge bread in liquid. Sprinkle evenly with cheese; cover with lightly greased (with cooking spray) aluminum foil, and chill at least 8 hours or up to overnight.
Remove dish from refrigerator; let stand 30 minutes. Preheat oven to 350°F. Bake in preheated oven, covered, for 30 minutes. Uncover and bake until lightly browned and set, about 15 minutes. Let stand 10 minutes before serving.
Prep this the day before—and sleep in a little the next morning!
Also appeared in: Health, December, 2019