Cut the head of cauliflower in half and then into quarters through the core. Then, run your knife between the florets and the stem and cut the stem out. Discard the stem and cut any large florets into smaller pieces.
To par-cook the cauliflower in the microwave, add it to a large microwave-safe bowl, and microwave on high for four minutes. You can also toss it in olive oil and roast it in a 425-degree oven for about 15 minutes.
Add the cooked cauliflower to an 8X8 baking dish, which has been sprayed with non-stick cooking spray. Sprinkle the bacon over the cauliflower. Set aside.
Add the eggs to a medium-size bowl and whisk well. Add the flour slowly, constantly whisking to prevent lumps. When the flour is incorporated, add in the milk and cream. Whisk to combine. Add the salt, pepper, and nutmeg and whisk to combine. Add one and one-half cups of the gruyere cheese and mix well.
Pour the milk and egg mixture evenly over the cauliflower and sprinkle the remaining cheese over the top.
Bake for 25-30 minutes until the casserole is puffed and golden and serve immediately.
If you don't have gruyere cheese, which adds a nutty, salty flavor to this dish, you can substitute Swiss, Emmental, Jarlsberg, or Raclette cheese.Easy Cauliflower Cheese Bake is substantial enough that you can also serve it as a meatless main dish. Make sure to drain your cauliflower thoroughly after cooking; if not, your casserole might be watery. Instead of par-cooking the cauliflower in the microwave, you can add it and two teaspoons of salt to a large pot of boiling water and cook for five minutes. Drain and rinse with cold water to stop the cooking process.Leftovers will keep covered in your fridge for up to four days. I don't recommend freezing them. You can reheat leftovers in the microwave for a minute or so.