Cheesy Broccoli Cauliflower Casserole (Cracker Crumb Topping)

One bowl of vegetables, one bowl of custard and a sleeve of buttery crackers. That is all it takes to put this cheesy broccoli and cauliflower casserole on the table, and most of the work is done before the oven even heats up. Lightly cooked florets are tossed in melted butter, covered with a rich mix of eggs, cream and three cheeses, then finished with bacon, green onions and a crunchy cracker crust.

In the oven, the egg and cream set into a soft, cheesy custard that holds the vegetables together, a bit like a crustless quiche, while the top turns golden and crisp. It is a dependable holiday side that pairs with turkey, ham or roast chicken, and it is just as welcome on an ordinary weeknight.

Ingredients

For the vegetables

• 2 to 3 cups (about 200 to 300 g) broccoli florets, bite-size.
• 2 to 3 cups (about 250 to 350 g) cauliflower florets, bite-size – or use all broccoli or all cauliflower, about 5 cups total.
• 4 tbsp (55 g) butter, melted.

For the cheesy custard

• 5 large eggs – they set the filling so it slices and scoops neatly.
• 1 1/2 cups (360 ml) heavy cream.
• 1 tsp onion powder and 1/2 tsp garlic powder.
• 3/4 tsp kosher salt and 1/2 tsp black pepper – go easy, as the cheese, bacon and crackers are salty.
• 1 cup (4 oz / 115 g) shredded extra-sharp cheddar, plus 1/2 to 1 cup more for the top.
• 1 cup (4 oz / 115 g) shredded mozzarella.
• 1/4 to 1/2 cup (25 to 50 g) grated Parmesan.
• 3 green onions, sliced, divided.

For the topping

• 6 slices bacon, cooked crisp and crumbled.
• 1 sleeve (about 35) round butter crackers, such as Ritz, crushed.
• 2 tbsp (30 g) butter, melted.

How to Make It

1. Blanch the florets – 3 minutes

Heat the oven to 350°F (175°C) and butter the baking dish. Bring a large pot of salted water to a boil, add the broccoli and cauliflower and cook for 2 to 3 minutes. Drain well and let them steam dry for a few minutes. The florets should be bright and just tender at the edges but still firm in the center; they keep cooking in the oven.

2. Toss with butter – 2 minutes

Toss the drained vegetables with the 4 tbsp of melted butter and spread them in the baking dish. Every floret should be lightly glossy.

3. Mix the custard – 5 minutes

In a separate bowl, whisk the eggs until smooth, then whisk in the cream, onion powder, garlic powder, salt and pepper. Stir in 1 cup of cheddar, the mozzarella, the Parmesan and about two thirds of the green onions. The mixture should be thick and evenly speckled with cheese, with no streaks of egg white.

4. Assemble – 5 minutes

Pour the cheesy custard evenly over the vegetables and nudge the florets so the mixture settles between them. Scatter the remaining cheddar over the top, then the bacon and the rest of the green onions. Most of the florets should be surrounded by custard, with only their tops peeking out.

5. Add the cracker crust – 3 minutes

Crush the crackers in a zip-top bag with a rolling pin or the bottom of a pan, then toss the crumbs with the 2 tbsp of melted butter. Sprinkle them over the casserole; you may not need them all. Aim for an even, generous layer that still lets a little cheese show through.

6. Bake – 350°F (175°C), 30 to 40 minutes

Bake uncovered until the edges are bubbling and the center is set. If the crackers brown too quickly, lay a sheet of foil loosely over the top. Let the casserole rest for 10 minutes before serving. It is done when the center no longer jiggles like liquid and a knife inserted near the middle comes out without runny egg. An instant-read thermometer in the center should read 160°F (71°C).

Fresh or Frozen Vegetables?

This recipe was written for fresh florets, but frozen broccoli and cauliflower work too. The main thing to manage is water. Florets that go into the dish wet release liquid as they bake, which thins the custard and leaves a watery layer at the bottom.

Whichever you choose, keep the pieces about the same size so they cook evenly, and do not skip the draining step.

Why the Custard Works

Many broccoli casseroles rely on canned soup or a flour-thickened cheese sauce. This one uses eggs and cream instead. As the casserole bakes, the egg proteins slowly set and bind the cream, cheese and vegetables into a soft, sliceable filling, the same way a quiche or a savory bread pudding sets.

Gentle heat is what keeps it creamy. At 350°F (175°C), the custard sets evenly from the edges toward the center. A hotter oven would make the eggs tighten and weep liquid before the middle is cooked. That is also why the casserole needs a short rest after baking: the center keeps setting as it cools slightly, and portions hold their shape when you scoop them.

The three cheeses each add something different. Extra-sharp cheddar brings the bold flavor, mozzarella makes the filling stretchy and creamy, and Parmesan adds a salty, savory depth, so you need very little extra salt.

Make Ahead and Leftovers

For the holidays, you can blanch the vegetables, cook the bacon and shred the cheese a day ahead. You can also assemble the vegetables and custard in the dish, cover and refrigerate it overnight. Add the cracker topping just before baking so it stays crisp, and allow 10 to 15 minutes more in the oven since the dish starts cold.

According to the USDA Food Safety and Inspection Service, casseroles made with eggs keep for 3 to 4 days in the refrigerator, and can be frozen for 2 to 3 months after baking. Refrigerate leftovers within 2 hours and reheat portions in the oven or microwave until hot all the way through. The cracker topping softens in the fridge; a few minutes in a hot oven or an air fryer brings back some of the crunch.

For more holiday sides and comfort food, try the chicken and stuffing casserole, the garlic herb roasted potatoes or a bowl of high-protein broccoli cheddar soup. For a lighter broccoli dish, there is the broccoli stir-fry with garlic sauce, and you can browse more ideas among the dinner recipes.

Cheesy Broccoli Cauliflower Casserole

Broccoli and cauliflower baked in a cheesy egg and cream custard with bacon, green onions and a buttery cracker crumb topping.

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Prep Time 25 minutes mins

Cook Time 40 minutes mins

Total Time 1 hour hr 5 minutes mins

Servings: 8 servings

Course: Side Dish

Cuisine: American

Calories: 560

Ingredients Method Notes

Ingredients

  

For the vegetables

• 2-3 cups broccoli florets bite-size
• 2-3 cups cauliflower florets bite-size
• 4 tbsp butter melted

For the cheesy custard

• 5 large eggs
• 1 1/2 cups heavy cream
• 1 tsp onion powder
• 1/2 tsp garlic powder
• 3/4 tsp kosher salt
• 1/2 tsp black pepper
• 1 1/2-2 cups shredded extra-sharp cheddar 1 cup for the custard, the rest for the top
• 1 cup shredded mozzarella
• 1/4-1/2 cup grated Parmesan
• 3 green onions sliced, divided

For the topping

• 6 slices bacon cooked crisp and crumbled
• 1 sleeve round butter crackers about 35, crushed
• 2 tbsp butter melted

Method

 

1. Heat the oven to 350°F (175°C) and butter a 9x13-inch baking dish. Boil the broccoli and cauliflower in salted water for 2 to 3 minutes, drain well and let steam dry.
2. Toss the vegetables with the 4 tbsp melted butter and spread them in the dish.
3. Whisk the eggs, cream, onion powder, garlic powder, salt and pepper. Stir in 1 cup cheddar, the mozzarella, Parmesan and most of the green onions.
4. Pour the custard over the vegetables. Top with the remaining cheddar, the bacon and the rest of the green onions.
5. Toss the crushed crackers with the 2 tbsp melted butter and sprinkle over the top.
6. Bake uncovered 30 to 40 minutes, until bubbling and set in the center (160°F / 71°C). Tent with foil if the crackers brown too fast. Rest 10 minutes before serving.

Notes

Storage: refrigerate leftovers within 2 hours and eat within 3 to 4 days, or freeze after baking for 2 to 3 months. Reheat until hot all the way through.

Make ahead: assemble the vegetables and custard the day before, refrigerate, then add the cracker topping and bake, adding 10 to 15 minutes.

Substitutions: all broccoli or all cauliflower; frozen florets, thawed and pressed dry; leave out the bacon for a vegetarian side.

Nutrition is an estimate based on standard ingredient values, not a laboratory analysis.