For the past 29 years (& for the foreseeable future), I have been well-known for not being a morning person. Most mornings you would be lucky to even get a smile or a genuine good morning from me. If I had a dollar for every time I hit snooze every morning, well, I’d be able to buy spend my earnings filming monthly Williams-Sonoma hauls, but I digress. My hack to waking up and getting my day started on the right foot is making breakfasts that are worth waking up for, and this is one of them.
This creamy cauliflower & leek breakfast casserole is savory, hearty, cheesy, and packed with protein. It reheats beautifully, too. It’s just as good for a quiet weekend brunch as it is for getting breakfast ready for the week.
There’s the unsung hero in the recipe: cream of chicken & mushroom soup.
I know it isn’t the most glamorous ingredient, but it works, okay? It gives the casserole that rich, creamy consistency without requiring a separate sauce, while the mushroom adds another layer of savory flavor that plays so well with the sausage and leeks.
For once, it’s the kind of cooking shortcut I can absolutely get behind.
Cauliflower and Leek Breakfast Casserole Recipe
Yield: 9 generous servings
Prep: 20 minutes
Cook: 40–50 minutes
Total: About 1 hour 10 minutes
Ingredients
Cauliflower Mixture
2 (12-oz) bags frozen or fresh cauliflower rice, about 6 cups
1 lb breakfast maple sausage, cooked and crumbled
2 medium leeks, white and light-green parts only, thinly sliced
5 oz fresh baby spinach
1 (10.5-oz) can cream of chicken soup
½ cup whole milk
1½ cups sharp cheddar, shredded and divided
1 tbsp Dijon mustard
1 tsp garlic powder
½ tsp onion powder
½ tsp smoked paprika
½ tsp dried thyme
½ tsp black pepper
Salt, to taste
2 tbsp butter or olive oil
Egg Mixture
10 large eggs
¼ cup whole milk
½ tsp garlic powder
¼ tsp black pepper
Pinch of salt
Instructions
1. Prep the cauliflower.
Thaw the cauliflower rice and squeeze out as much moisture as possible. Heat a large skillet over medium-high heat and cook the cauliflower for 8–10 minutes in a dry skillet, stirring occasionally, until mostly dry and lightly golden. Transfer to a large bowl.
2. Cook the sausage.
In the same skillet, cook the sausage until browned and cooked through, breaking it into small pieces. Drain excess grease if needed. Add to the cauliflower.
3. Cook the leeks & spinach.
Add the butter or oil to the skillet. Cook the leeks over medium heat for 7–10 minutes, until soft and lightly golden. Add the spinach and cook for 1–2 minutes, until wilted. Add to the cauliflower mixture.
4. Make it creamy.
Whisk together the cream of chicken soup, ½ cup milk, Dijon, garlic powder, onion powder, smoked paprika, thyme, and black pepper. Pour over the cauliflower mixture. Add 1 cup cheddar and stir until evenly combined.
5. Make the egg mixture.
Whisk the eggs, ¼ cup milk, garlic powder, black pepper, and salt until smooth.
6. Assemble.
Grease a 9×13-inch baking dish. Spread the cauliflower mixture evenly into the dish, then pour the eggs over top. Gently shake the dish to help the eggs settle throughout. Sprinkle with the remaining ½ cup cheddar.
7. Bake.
Bake uncovered at 350°F for 40–50 minutes, until the center is set and the cheese is melted and lightly golden. If the top browns too quickly, loosely tent with foil.
Rest for 10–15 minutes before slicing.
Notes from Neutral Kitchen 🤎
Don’t skip squeezing the cauliflower. Frozen cauliflower rice holds a surprising amount of water. Removing as much moisture as possible—and cooking it down before assembling—keeps the casserole creamy instead of watery.
Fresh cauliflower rice works, too. You can use about 6 cups fresh cauliflower rice. There’s no need to thaw it, but still cook it in the skillet until the excess moisture has cooked off.
The cream of chicken soup is the secret. It gives this casserole its creamy, savory texture without requiring a separate sauce. The mushroom flavor also adds a little extra depth alongside the sausage and leeks.
Make it ahead. Assemble the casserole the night before, cover, and refrigerate. Let it sit at room temperature for about 20–30 minutes before baking. You may need to add a few extra minutes to the bake time.
For meal prep: Let the casserole cool completely before slicing into 9+ portions. Store in an airtight container in the refrigerator for up to 4 days. Reheat individual portions in the microwave until warmed through.