This cheesy beef casserole is a one-dish dinner of seasoned ground beef, wilted spinach, and cauliflower rice under a layer of golden cheddar. I brown the beef with a small onion, garlic powder, Italian seasoning, and a pinch of red pepper flakes, then wilt fresh spinach into the same pan. While the beef cooks, a bag of frozen cauliflower rice steams in the microwave, and I stir it together with sour cream right in the 9×13-inch baking dish. The beef and spinach go in next, the cheddar goes on top, and a 475°F oven melts and browns the cheese in about 13 minutes. It takes about 30 minutes from start to finish and makes 8 servings.
You do not need to drain the beef after browning it. The sour cream keeps the cauliflower rice and beef filling creamy under the cheese. Let the casserole cool for a few minutes before slicing so the pieces hold together.
The recipe runs on two tracks at once: the cauliflower rice cooks in the microwave while the beef browns on the stovetop. Measure the spices and have the spinach ready before you start so you are not hunting for anything mid-cook. If you like hearty beef dinners, my Creamy Ground Beef Skillet with Cauliflower Rice and Stuffed Bell Pepper Casserole are two more to try.
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Reader Love
I made this dish last night. I doubled the recipe. I used cheddar, mozzarella, and Mexican cheese blend to use up some cheeses I had left over. It was soooo delicious. I had some non believers that don’t like cauliflower rice and it changed their mind. I will be making again.
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💛 Why you’ll love this recipe
- 30 minutes, start to finish: The cauliflower rice cooks in the microwave while the beef browns on the stovetop. By the time the beef is seasoned and the spinach is wilted, the cauliflower rice is ready to go into the casserole dish.
- A hot oven browns the cheese: Baking at 475°F for about 13 minutes gives the finely shredded cheddar on top real color, golden and bubbly instead of just melted.
- 8 servings from one pan: The recipe fills a 9×13-inch casserole dish, enough for a family dinner with leftovers that reheat well.
- Simple seasoning: Garlic powder, Italian seasoning, and red pepper flakes give the beef plenty of flavor without any sauce, and all three are everyday pantry spices.
- Eight cups of spinach cook down: The 8 ounces of fresh spinach go into the pan in small batches after the beef is cooked and wilt down in about a minute. You get spinach in every bite without it taking over the texture of the casserole.
- Cast iron works too: If you don’t have a casserole dish, use a large cast iron skillet instead. Once the spinach is wilted, add the cauliflower rice and sour cream directly to the skillet, stir to combine, top with cheese, and bake as written. That leaves one less dish to wash.
➡️ Ingredients
⏲ How to make this recipe
This is an overview of the recipe’s instructions. The full instructions can be found in the recipe card at the bottom of this post.
- Cook Cauliflower Rice: Cook the frozen cauliflower rice in the microwave, according to the package instructions.
- Cook Beef: While the cauliflower rice cooks, in a large hot and oiled skillet, cook some onions until fragrant. Add in ground beef and cook, breaking the meat up as it cooks. Once the beef is mostly cooked through, stir in spices. You do not need to drain the beef.
- Add In And Wilt Spinach: Reduce the heat to medium, then add the spinach to the pan of cooked beef in small batches and cook until wilted, stirring occasionally.
- Prepare Casserole: To a 9×13-inch baking dish, add the steamed cauliflower rice and some sour cream and stir together. Add in the spinach and beef mixture, stir again, and then flatten all of that into an even layer. Sprinkle shredded cheddar cheese on top of the dish.
- Bake Casserole: Transfer the casserole dish to the oven and bake at 475°F until the cheese is golden and bubbling, about 13 minutes.
- Serve: Remove the dish from the oven and allow it to cool slightly before slicing and serving.
👉 Easy ingredient swaps
- Frozen steamable cauliflower rice: Fresh cauliflower rice works in its place, which you can make by pulsing raw cauliflower florets in a food processor until they’re the size of rice grains. You can also use steamed florets cut into small pieces. They will be a little chunkier but hold up in the dish.
- Ground beef: Ground turkey, ground chicken, or ground sausage all work well. If you use sausage, keep in mind it brings its own seasoning, so taste the mixture before adding extra spices.
- Sour cream: Greek yogurt swaps in at a 1:1 ratio and holds up through baking without breaking down.
- Fresh spinach: Frozen spinach works, but thaw it completely first and squeeze out as much liquid as you can before adding it to the pan with the cooked beef to heat through. Skipping the squeeze step will make the casserole watery.
- Shredded cheddar: Any meltable cheese works here. One reader used a combination of cheddar, mozzarella, and a Mexican cheese blend to finish off partial bags, and liked how it turned out.
✨ Variations
- Stir in 1 to 2 tablespoons of tomato paste, or ¼ cup of tomato sauce, into the ground beef as it finishes cooking for a richer, more savory filling.
- Add a handful of chopped fresh tomatoes to the pan when you add the spinach for a fresh, bright note in every bite.
- Try chili powder, cumin, or dried oregano if you want a different mix of spices. All three go well with the Italian seasoning already in the dish.
- Bake in a large cast iron skillet instead of a casserole dish: after wilting the spinach, add the cauliflower rice and sour cream directly to the skillet, stir together, top with cheese, and bake as the recipe instructs.
〰️ How to serve
- Serve it with a crisp salad. The Creamy Dill Cucumber Onion Salad pairs naturally here since its sour cream dressing echoes the casserole’s base.
- Roasted vegetables or a Fresh Corn Salad add color and a lighter contrast on the side.
- A piece of crusty baguette on the side rounds out the meal.
- With 8 servings from one pan, the casserole also works for meal prep. Leftovers keep for up to 3 days in the refrigerator and reheat without drying out.
💬 FAQs
How do I store leftovers?
Store the cooked casserole in an airtight container in the refrigerator for up to 3 days. The beef and cheese reheat without drying out, and the dish is just as good the next day.
Can I freeze this casserole?
Yes. Let the casserole cool completely before transferring it to a freezer-safe airtight container. It will keep for up to 2 months. When you’re ready to serve it, thaw it overnight in the refrigerator before reheating.
What’s the best way to reheat leftovers?
For a single portion, microwave it until heated through, about 30 to 60 seconds, depending on your microwave’s wattage. For a larger amount, transfer it to a casserole dish and reheat in a 450°F oven until hot throughout. Both methods work well.
Can I use frozen spinach instead of fresh?
Yes, with one key step: thaw the frozen spinach completely first, then squeeze out as much liquid as possible before adding it to the pan with the cooked beef. Skipping the squeeze will leave excess water in the casserole and make it too wet.
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Cheesy Beef Casserole with Cauliflower Rice and Spinach
Ingredients
- 10 ounces frozen steamable cauliflower rice, (I use Green Giant)
- 1 tablespoon avocado oil
- 1 small onion, finely chopped
- 1 pound ground beef
- 1 ½ teaspoon garlic powder
- 1 ½ teaspoon Italian seasoning
- ¼ teaspoon red pepper flakes
- ¼ teaspoon salt
- ⅛ teaspoon pepper
- 8 ounces (~8 cups) fresh spinach
- 1 cup sour cream
- 1 ⅓ cup finely shredded cheddar cheese
Instructions
- Preheat Oven: Preheat oven to 475°F.
- Cook Cauliflower Rice: Cook frozen cauliflower rice in microwave, according to package instructions.
- Cook Beef: While cauliflower rice cooks, in a large pan over medium-high heat, heat oil. Once hot, add onions and cook until fragrant, about 1 minute. Add ground beef and cook, breaking meat up as it cooks. Once beef is mostly cooked through, about 5 minutes, stir in garlic powder, Italian seasoning, red pepper flakes, salt, and pepper.
- Add In And Wilt Spinach: Reduce stovetop heat to medium. Add spinach to the pan of cooked beef in small batches and cook until wilted, about 1 minute, stirring occasionally.
- Prepare Casserole: To a 9×13-inch casserole dish, add in steamed cauliflower rice and sour cream and stir together until well combined. Add cooked beef and spinach mixture, stir again, then flatten into an even layer. Top dish with shredded cheddar.
- Bake Casserole: Transfer casserole dish to oven and bake until cheese is golden and bubbling, about 13 minutes.
- Serve: Remove dish from oven and allow to cool slightly before slicing and serving.
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