Broccoli Cauliflower Bake (Vegetable Au Gratin) Recipe

I’m excited to share my Broccoli Cauliflower Bake with a clever pantry shortcut and a little twist that will make dinner planning much easier.

I never thought a simple tray of vegetables could make me look like I planned something fancy, but this Broccoli Cauliflower Bake did just that. Tender florets get swallowed by a creamy sauce then smothered in sharp cheddar, and a golden breadcrumb topping that crunches loud when you dig in.

I kept telling myself one more bite, but it kept getting better, weirdly. There’s a little tang that wakes up the whole thing so it never feels dull.

I bring it to dinners when I want people to ask for the recipe, but not guess how easy it was.

Ingredients

• Broccoli: Crunchy, fiber rich, vitamin C and K, adds green freshness and mild bitterness.
• Cauliflower: Neutral, starchy, good source of fiber and vitamin C, soaks up cheesy flavors.
• Sharp cheddar: Bold, salty, protein rich, melts into a gooey, savory backbone for bake
• Parmesan: Salty, nutty, concentrated umami, adds crusty savory punch when sprinkled on top.
• Milk and butter roux: Makes creamy sauce, adds fat and calcium, thickens and coats vegs.
• Dijon mustard: Gives tang and depth, brightens sauce without stealing the show.
• Nutmeg: Tiny warm spice note, complements cheese, easy to forget but makes its cozy.
• Breadcrumbs/panko: Crispy topping, adds crunch and texture, makes dish feel toasted and rustic.

Ingredient Quantities

• 4 cups broccoli florets
• 4 cups cauliflower florets
• 3 tablespoons unsalted butter
• 3 tablespoons all purpose flour
• 2 1/2 cups whole milk
• 1 teaspoon Dijon mustard
• 1/4 teaspoon ground nutmeg
• 1 teaspoon kosher salt
• 1/2 teaspoon freshly ground black pepper
• 2 cups sharp cheddar, shredded
• 1/2 cup grated parmesan
• 3/4 cup plain breadcrumbs or panko
• 2 tablespoons butter melted
• Optional 1/2 cup Gruyere or mozzarella, shredded

How to Make this

1. Preheat oven to 375°F and grease a 9×13 inch baking dish (or a similar sized casserole dish).

2. Bring a large pot of salted water to a boil. Add the broccoli and cauliflower florets and blanch for 2 minutes until bright and just tender. Drain and immediately plunge into ice water to stop cooking, then drain very well.

3. In a medium saucepan melt 3 tablespoons butter over medium heat. Whisk in 3 tablespoons flour and cook 1 to 2 minutes until foamy but not browned.

4. Slowly whisk in 2 1/2 cups whole milk, bring to a gentle simmer and cook until the sauce thickens and coats the back of a spoon, about 5 to 7 minutes. Stir in 1 teaspoon Dijon, 1/4 teaspoon nutmeg, 1 teaspoon kosher salt and 1/2 teaspoon black pepper; taste and adjust if needed.

5. Turn heat to low and stir in 1 1/2 cups shredded sharp cheddar and the 1/2 cup grated parmesan until melted and silky. If you’re using the optional 1/2 cup Gruyere or mozzarella add it now and melt it in. Remove sauce from heat.

6. Toss the drained broccoli and cauliflower with the cheese sauce until everything is evenly coated and transfer to the prepared baking dish. Sprinkle the reserved 1/2 cup cheddar over the top if you like extra cheesiness.

7. Mix 3/4 cup breadcrumbs with the 2 tablespoons melted butter and a pinch of salt and pepper. Evenly sprinkle the breadcrumb mixture over the casserole.

8. Bake at 375°F for 20 to 25 minutes until bubbly and the top is golden. If you want a crispier, deeper brown top, switch to broil for 1 to 2 minutes but watch it closely so it dont burn.

9. Let the bake rest 5 to 10 minutes before serving so the sauce firms up a bit. Serve warm and enjoy.

Equipment Needed

1. 9 by 13 inch baking dish or similar casserole dish, greased
2. Large pot for boiling the broccoli and cauliflower
3. Colander for draining the veggies
4. Large bowl for ice water to stop the cooking
5. Medium saucepan for making the cheese sauce
6. Whisk and a wooden spoon or heatproof spatula, you’ll stir a lot so have both ready
7. Measuring cups and measuring spoons for milk, flour, butter and spices
8. Box grater or microplane for the parmesan (or buy pre grated if you want)
9. Small bowl and a spoon to mix the breadcrumbs with melted butter
10. Oven mitts and a rimmed baking sheet if you plan to broil the top, dont get burned

FAQ

Broccoli Cauliflower Bake (Vegetable Au Gratin) Recipe Substitutions and Variations

• Whole milk: swap for half and half if you want a richer sauce, or use 2%/skim plus 1 tablespoon cornstarch whisked into the milk to keep it thick. Unsweetened soy or oat milk work too but use full fat versions and expect a slightly different flavor.
• Unsalted butter: use ghee for a nuttier note, or extra virgin olive oil for a dairy free option (use same volume). If you use salted butter cut the added salt by about 1/4 teaspoon.
• All purpose flour: for gluten free use a 1 to 1 gluten free flour blend, or use 1 1/2 tablespoons cornstarch mixed into a little cold milk first since cornstarch thickens more than flour.
• Sharp cheddar: swap with Gruyere, Fontina, or a mix of mozzarella plus extra Parmesan for good melt and flavor. If you pick a milder cheese add a bit more cheese or an extra pinch of Dijon for brightness.

Pro Tips

1) Get the florets really dry. After blanching spin them in a salad spinner and pat with towels, or the sauce will get watery and thin out. I always let them sit on a towel for a few minutes because even a little moisture ruins the texture.

2) Warm the milk and add it slowly while whisking so you dont get lumps. Cook the flour and butter just long enough to lose the raw taste but dont let it brown, otherwise the sauce can taste grainy or burnt.

3) Always grate your own cheese from blocks. Pre-shredded cheese has anti caking stuff and it wont melt as smooth. Also mix a sharp cheddar with a more melty cheese for the best creamy + stringy balance, and let the cheese come close to room temp so it melts faster.

4) For a super crunchy top, toast the breadcrumbs in a skillet with the melted butter and a pinch of salt and garlic powder before sprinkling on. If you need to make it ahead, assemble, cover and chill, then add 10 to 15 extra minutes baking time from cold and let it rest after baking so the sauce firms up.

Broccoli Cauliflower Bake (Vegetable Au Gratin) Recipe

Recipe by Belinda Ecclestone

0.0 from 0 votes

I’m excited to share my Broccoli Cauliflower Bake with a clever pantry shortcut and a little twist that will make dinner planning much easier.

Pin

Servings

6

servings

Calories

429

kcal

Equipment: 1. 9 by 13 inch baking dish or similar casserole dish, greased
2. Large pot for boiling the broccoli and cauliflower
3. Colander for draining the veggies
4. Large bowl for ice water to stop the cooking
5. Medium saucepan for making the cheese sauce
6. Whisk and a wooden spoon or heatproof spatula, you’ll stir a lot so have both ready
7. Measuring cups and measuring spoons for milk, flour, butter and spices
8. Box grater or microplane for the parmesan (or buy pre grated if you want)
9. Small bowl and a spoon to mix the breadcrumbs with melted butter
10. Oven mitts and a rimmed baking sheet if you plan to broil the top, dont get burned

Ingredients

• 4 cups broccoli florets

• 4 cups cauliflower florets

• 3 tablespoons unsalted butter

• 3 tablespoons all purpose flour

• 2 1/2 cups whole milk

• 1 teaspoon Dijon mustard

• 1/4 teaspoon ground nutmeg

• 1 teaspoon kosher salt

• 1/2 teaspoon freshly ground black pepper

• 2 cups sharp cheddar, shredded

• 1/2 cup grated parmesan

• 3/4 cup plain breadcrumbs or panko

• 2 tablespoons butter melted

• Optional 1/2 cup Gruyere or mozzarella, shredded

Directions

• Preheat oven to 375°F and grease a 9×13 inch baking dish (or a similar sized casserole dish).
• Bring a large pot of salted water to a boil. Add the broccoli and cauliflower florets and blanch for 2 minutes until bright and just tender. Drain and immediately plunge into ice water to stop cooking, then drain very well.
• In a medium saucepan melt 3 tablespoons butter over medium heat. Whisk in 3 tablespoons flour and cook 1 to 2 minutes until foamy but not browned.
• Slowly whisk in 2 1/2 cups whole milk, bring to a gentle simmer and cook until the sauce thickens and coats the back of a spoon, about 5 to 7 minutes. Stir in 1 teaspoon Dijon, 1/4 teaspoon nutmeg, 1 teaspoon kosher salt and 1/2 teaspoon black pepper; taste and adjust if needed.
• Turn heat to low and stir in 1 1/2 cups shredded sharp cheddar and the 1/2 cup grated parmesan until melted and silky. If you're using the optional 1/2 cup Gruyere or mozzarella add it now and melt it in. Remove sauce from heat.
• Toss the drained broccoli and cauliflower with the cheese sauce until everything is evenly coated and transfer to the prepared baking dish. Sprinkle the reserved 1/2 cup cheddar over the top if you like extra cheesiness.
• Mix 3/4 cup breadcrumbs with the 2 tablespoons melted butter and a pinch of salt and pepper. Evenly sprinkle the breadcrumb mixture over the casserole.
• Bake at 375°F for 20 to 25 minutes until bubbly and the top is golden. If you want a crispier, deeper brown top, switch to broil for 1 to 2 minutes but watch it closely so it dont burn.
• Let the bake rest 5 to 10 minutes before serving so the sauce firms up a bit. Serve warm and enjoy.

Notes

• Below you’ll find my best estimate of this recipe’s nutrition facts. Treat the numbers as a guide rather than a rule—great food should nourish both body and spirit. Figures are approximate, and the website owner assumes no liability for any inaccuracies in this recipe.

Nutrition Facts

• Serving Size: 308g
• Total number of serves: 6
• Calories: 429kcal
• Fat: 30.6g
• Saturated Fat: 17.4g
• Trans Fat: 0.13g
• Polyunsaturated: 2.45g
• Monounsaturated: 7.65g
• Cholesterol: 80.6mg
• Sodium: 598mg
• Potassium: 512mg
• Carbohydrates: 26.1g
• Fiber: 3.5g
• Sugar: 6.25g
• Protein: 20.1g
• Vitamin A: 800IU
• Vitamin C: 88mg
• Calcium: 547mg
• Iron: 1.18mg