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Cheesy Cauliflower Casserole

Jessica T. Brown
A creamy, cheesy cauliflower casserole baked with sour cream, sharp cheddar, and a savory finish of bacon and scallions.
Low-carb, fiber-packed, and ready in just 30 minutes — a comforting side or light main dish.
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Prep Time 15 minutes
Cook Time 15 minutes
Total Time 30 minutes
Course Side Dish
Cuisine American
Servings 6

Equipment

  • 1 Rimmed Baking Sheet
  • Parchment Paper (1 sheet)
  • 1 Large mixing bowl
  • 1.5-Quart Baking Dish
  • 1 Box Grater

Ingredients
  

  • 1 large cauliflower head about 1.5 lbs, cut into small florets
  • Olive oil spray as needed
  • 1 teaspoon kosher salt or ½ teaspoon table salt
  • ¼ teaspoon black pepper
  • ½ cup sour cream
  • 2 tablespoons whole milk
  • 1 teaspoon Dijon mustard
  • 1 teaspoon fresh garlic minced
  • 1 pinch cayenne pepper
  • 1 cup sharp cheddar cheese shredded (divided, about 4 oz)
  • 2 tablespoons bacon bits for garnish
  • 2 tablespoons scallions thinly sliced (green tops only)

Instructions
 

  • Prepare the Oven and Pan: Preheat your oven to 425°F (220°C) and line a large rimmed baking sheet with parchment paper.
    This step prevents the cauliflower from sticking and makes cleanup quick and effortless.
  • Roast the Cauliflower: Spread the cauliflower florets evenly across the lined baking sheet, making sure not to overcrowd them.
    Generously spray with olive oil, then sprinkle with salt and black pepper.
    Roast for about 12 minutes, or until the florets are tender-crisp and lightly golden around the edges.
  • Mix the Creamy Base: While the cauliflower roasts, combine sour cream, whole milk, Dijon mustard, minced garlic, cayenne pepper, and half of the shredded cheddar in a large mixing bowl.
    Stir until smooth, creamy, and evenly blended.
  • Combine Flavors: Once the cauliflower is finished roasting, carefully transfer the warm florets into the prepared sour cream mixture.
    Toss gently but thoroughly, ensuring each piece is coated with the rich, cheesy sauce.
  • Assemble the Casserole: Lightly grease a 1.5-quart baking dish with cooking spray or butter.
    Spoon the cauliflower mixture into the dish, spreading it evenly.
    Sprinkle the remaining shredded cheddar cheese over the top for a bubbly, golden finish.
  • Bake to Perfection: Place the dish back into the hot oven and bake for 8–10 minutes, or until the cheese on top is fully melted and slightly browned.
    This short bake time locks in the flavors without overcooking the cauliflower.
  • Garnish and Serve: Remove the casserole from the oven and allow it to cool for 2–3 minutes.
    Sprinkle bacon bits and fresh scallions over the top for crunch and color.
    Serve warm as a side dish or enjoy as a satisfying light entrée.

Notes

  • If using pre-cut cauliflower, check for larger florets and trim them to match the smaller ones.
  • Frozen cauliflower works, but it requires around 30 minutes of roasting instead of 12. No need to brown it, just roast until tender.
  • For a heartier meal, mix in cooked, shredded chicken and double the sour cream for extra creaminess.
  • Leftovers taste best when reheated gently at 50% power in the microwave; avoid freezing as the texture becomes watery.
  • Freshly shredded cheddar melts better than pre-shredded versions, which often contain anti-caking agents that affect texture.
  • Adjust seasoning to your taste — add smoked paprika for a smoky kick or extra cayenne for more heat.