Step 1 of 20
Super Cheesy Cauliflower "Mac" and Cheese
Preheat the oven to 400°F.
Step 2 of 20
Super Cheesy Cauliflower "Mac" and Cheese
Line a large baking sheet with a silicone baking mat or parchment paper. Set aside.
Step 3 of 20
Super Cheesy Cauliflower "Mac" and Cheese
Spray a 9x13-inch baking dish with nonstick cooking spray. Set aside.
Step 4 of 20
Super Cheesy Cauliflower "Mac" and Cheese
Using a cheese grater or food processor fitted with a grating attachment, grate the Cheddar and Gruyere cheeses. Set aside.
PRO TIP In a hurry? Use pre-shredded cheese instead of freshly-grated cheese.
Step 5 of 20
Super Cheesy Cauliflower "Mac" and Cheese
Transfer the grated cheese to a large bowl, and add the Parmesan cheese. Set aside.
Step 6 of 20
Super Cheesy Cauliflower "Mac" and Cheese
Cut the cauliflower into 1-inch florets.
Step 7 of 20
Super Cheesy Cauliflower "Mac" and Cheese
Arrange the cauliflower florets on the prepared baking sheet. Drizzle with olive oil and season with salt and pepper. Stir to distribute the seasoning.
Step 8 of 20
Super Cheesy Cauliflower "Mac" and Cheese
Roast the cauliflower on middle rack of oven until it can be pierced with a fork, but is not tender, about 20 minutes.
Step 9 of 20
Super Cheesy Cauliflower "Mac" and Cheese
When cauliflower is done, remove from oven and set aside.
Step 10 of 20
Super Cheesy Cauliflower "Mac" and Cheese
Reduce the oven temperature to 350°F.
Step 11 of 20
Super Cheesy Cauliflower "Mac" and Cheese
In a large pot over medium heat, melt the butter.
Step 12 of 20
Super Cheesy Cauliflower "Mac" and Cheese
Once melted, add the flour and whisk to thoroughly combine. Continue whisking until the roux turns slightly golden and begins to smell toasty, about 1 minute.
Step 13 of 20
Super Cheesy Cauliflower "Mac" and Cheese
Slowly stream the milk into the pot while continuing to whisk. Cook the mixture, whisking steadily, until it begins to thicken and bubble, about 4 minutes.
Step 14 of 20
Super Cheesy Cauliflower "Mac" and Cheese
Once mixture thickens and bubbles, turn off the heat. Add the mustard powder, garlic powder, salt, and black pepper.
Step 15 of 20
Super Cheesy Cauliflower "Mac" and Cheese
Add 3/4 of the cheese to the pot one handful at a time, whisking slowly after each addition. Reserve a generous 1 cup for topping.
Step 16 of 20
Super Cheesy Cauliflower "Mac" and Cheese
Once the sauce is smooth, add the roasted cauliflower to the pot. Stir until combined.
Step 17 of 20
Super Cheesy Cauliflower "Mac" and Cheese
Pour the contents of the pot into the prepared baking dish. Sprinkle the reserved cheese in an even layer over the top of the cauliflower.
Step 18 of 20
Super Cheesy Cauliflower "Mac" and Cheese
Bake cauliflower mac on middle rack of oven until the edges are bubbling and the top is lightly browned, 15-18 minutes
Step 19 of 20
Super Cheesy Cauliflower "Mac" and Cheese
Check to see that cauliflower mac is done. Remove from oven or add time as needed.
Step 20 of 20
Super Cheesy Cauliflower "Mac" and Cheese
Allow dish to rest for about 15 minutes before serving.