Cheddar Broccoli Cauliflower Gratin | Ambitious Kitchen

Every Christmas eve, my husband’s good family friend, Lori, throws a huge celebration filled with food, cocktails and good company. She makes incredible savory chicken and dumplings, an outrageously good apple walnut spinach salad and just last year she introduced a new-to-me cheesy veggie gratin filled with cauliflower, carrots and broccoli.

I knew I really liked it after one bite of cheddar cheesy goodness, but after scooping seconds and then thirds onto my plate, I realized that a true love affair was going down between me and this fabulous gratin.

A couple of years ago I decided to bring my version of Lori’s cheddar broccoli cauliflower gratin to you, and of course, in consideration for your Thanksgiving menu (aka my favorite day).

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What is a “gratin?”

Gratin refers to a recipe that’s topped with butter, cheese and/or breadcrumbs and then baked so that a nice crust forms. In my dad’s cheesy au gratin potatoes the potatoes are covered in a delicious cheese sauce and baked to bubbly perfection. In this cauliflower broccoli gratin we’re adding both cheese sauce and breadcrumbs to get a lovely toasty texture on top.

Ingredients in this cheddar broccoli cauliflower gratin

This isn’t your average butter-filled veggie gratin. Instead, it’s made with a lightened-up sharp cheddar cheese sauce that only uses a few tablespoons of butter, yet is still rich, flavorful and generously coats all of the veggies with plenty of cheesy love. You’ll only need a few simple, inexpensive ingredients to make the recipe (and they’re all from ALDI!)

• Cauliflower, broccoli & carrots: this is what was in Lori’s gratin, and now it’s in mine too! You’ll want to make sure your florets aren’t too large, otherwise they won’t all fit nicely in your pan.
• Butter: I prefer salted butter in both cooking and baking, simply because it adds just a little more flavor.
• Flour: you can use regular flour, but know that whole wheat or a 1:1 gluten-free all purpose flour are also options.
• Milk: I love using unsweetened almond milk in all of my baking and cooking, but you can also use regular milk if that’s your preference.
• Garlic powder: essential for adding additional flavor to the cheese sauce!
• Cheese: I always recommend shredding your own cheese from a block of cheese, as it tends to melt better! We’re using cheddar for extra delicious flavor.
• Parmesan: in addition to cheddar, we’re using parmesan cheese for nice, cheesy flavor
• Panko breadcrumbs: while topping this gratin is optional, I do recommend it! Everyone loves a good crunchy breadcrumb coating.

Can I make it vegan?

Sure! Feel free to use vegan butter and your favorite vegan cheeses in this recipe to make a dairy free and vegan cauliflower broccoli gratin. Be sure to use a dairy free milk as well.

Easy ways to customize

This cheddar broccoli cauliflower gratin is easy to make and even easier to customize! Here are some great ways to make it your own:

• Choose your cheese. I love the flavor that cheddar gives this dish but feel free to use your favorite cheese! Gruyere, a smoky gouda, or even a spicy cheese would be delicious.
• Go extra savory. If you’re not serving vegetarians I think adding cooked bacon or ham to the cheese sauce would be SO delicious.
• Pick the veggie ratio. Feel free to use any combo of veggies you’d like! All cauliflower or all broccoli would work just as well.

Cheesy cauliflower broccoli gratin in 5 simple steps

1. Prep your pan. Start by greasing a 2 1/2 quart baking dish and adding all of your veggies.
2. Make the cheese sauce. Melt butter in a skillet over medium heat and make a roux by alternating flour and milk. Bring the mixture to a boil, then reduce it to low and stir it every so often until a gravy-like texture forms. Stir in the garlic powder, salt & pepper, then fold in the cheeses.
3. Assemble the gratin. Pour your cheese sauce all over those veggies, cover with foil and bake.
4. Prep your breadcrumbs. While the gratin is baking, mix breadcrumbs with melted butter.
5. Top, bake & serve. Remove the gratin from the oven, top with breadcrumbs, and then bake it again until veggies are fork tender. Serve & enjoy!

Make it ahead of time

If you want to make this recipe ahead of time and save time on Thanksgiving Day, simply make the recipe as directed, except do NOT add breadcrumbs. Instead, cover and place in the fridge for up to a day or two. Once ready to enjoy, bake as directed in the instructions, adding the breadcrumbs after 30 minutes of baking, then baking again uncovered.

Storing & reheating tips

• To store: simply store this broccoli cauliflower gratin in the refrigerator in individual, airtight containers or cover the entire pan and place it in the refrigerator. It will stay good for up to 5 days.
• To reheat: reheat individual portions in the microwave or place the pan back in the oven until heated through.

More delicious Thanksgiving recipes

Get all of our Thanksgiving recipes here, and our best tips for hosting here!

This recipe is perfect to serve during Thanksgiving, or just anytime you’re looking for a healthy, yet deliciously cheesy and easy side dish!

I hope you all love this cheddar broccoli cauliflower gratin! If you make it be sure to leave a comment and a rating so I know how you liked it. Enjoy, xo!