“Cauliflower is nothing but cabbage with a college education.” – Mark Twain (Cauliflower Quote)
This Cheesy Cauliflower Gratin Casserole is easy to make and is a great low carb side dish. Cauliflower is one of the unsung heroes of the vegetable kingdom. This elegant crown has a subtle flavor that makes it easy to pair with other flavors. But it has plenty to offer all on its own, with 1 cup providing well over half your daily requirement for Vitamin C.
You can also make this with a different cheese and change up the flavor. For example, try pepper jack or provolone! This cauliflower mac and cheese is a similar recipe that spices it up with jalapenos and bacon.
While I consider it keto, this recipe does use of the flour used to thicken it. However, you can use something like arrowroot to make it strictly keto. It is very low carb regardless.
- 1 head cauliflower
- 2 tablespoons unsalted butter
- 3 tablespoons all-purpose flour
- 1 teaspoon dry mustard
- Pinch kosher salt
- 1 cup low fat milk
- 1 cup plain Greek-style yogurt (reduced fat)
- ½ cup grated aged Cheddar cheese
- Freshly ground pepper
- Preheat the oven to 375 degrees F. Spray a baking dish or a 3-quart casserole dish with cooking spray.
- Cut away the outer leaves from the cauliflower and then cut the head in half. Cut out the core to separate the cauliflower into bite-size florets. Bring a large pot of lightly salted water to a boil and add the cauliflower. Boil until the cauliflower is tender, about 8 minutes. Drain in a colander and let cool
- Heat the butter in a saucepan over medium heat. When the butter stops foaming, add the flour and mustard and stir to a smooth paste. Reduce the heat to low and cook, stirring, until a light golden color with a nutty aroma, about 6 minutes.
- Whisk in the milk until there are no lumps. Return the sauce to a simmer and cook until thickened, about 10 minutes. Remove the pan from the heat and stir in the yogurt and cheese. Spoon this sauce evenly over the cauliflower.
- Bake until the sauce is golden brown on top and bubbling, about 30 minutes.

The ingredients listed includes dry mustard. However, the directions to not include this ingredient. At what point do you add this missing ingredient?
Sorry about that! Add the mustard with the flour, I updated the recipe. It also tastes great without the mustard.
When do you add the dry mustard and can you substitute prepared mustard if so what kind?
Sorry about that! I left it out of the instructions! Add the mustard with the flour, I updated the recipe. It also tastes great without the mustard. If you want to sub prepared mustard that is fine. I would use either yellow or dijon.
It’s a shame that the recipe uses flour – 4g carbs per cup makes it out of reach for most people on a Keto diet unless the serving size is really small. That would be difficult as it look delicious.
You can use Xatham Gum or Tapioca starch instead to thicken it instead, which will reduce the carbs a bit more. You could also leave out the flour, but it will not have a thick sauce. That maybe could be remedied by adding more cheese.
Can you use Almond or Coconut flour instead?
The flour in this is used for thickening, and almond and coconut flour don’t work well for that. But you could try tapioca starch or xanthan gum in place of the flour to thicken it. You could also try adding more cheese to make it thicker and omitting the flour.