Bring a big pot of salted water to a boil and toss in your pasta and broccoli. Cook them together, following the pasta package directions for al dente—or take them out about 2 minutes early if you like a firmer bite.

While that’s cooking, lightly spray a baking dish with cooking spray and set it aside.

Preheat your oven to 375°F.

In a large skillet, melt the butter over low heat. Add the chopped onion and cook for about 2 minutes until it starts to soften.

Sprinkle in the flour and stir for another minute, just until it turns a light golden color and blends in nicely.

Slowly pour in the milk and chicken broth, whisking as you go. Turn the heat up to medium-high and let it bubble away for around 5 minutes, or until the sauce is smooth and thick. Season with a bit of salt and pepper.

Once the sauce has thickened, take it off the heat and stir in the cheese until it’s fully melted and creamy. Taste and adjust the salt and pepper if needed.

Now, add the cooked pasta and broccoli to the cheesy sauce and stir everything together until nicely coated.

Pour the mixture into your prepared baking dish. Sprinkle some extra cheese and breadcrumbs on top, then give it a quick spray of cooking spray to help it crisp up.

Bake for 15–20 minutes, then finish it off under the broiler for a few minutes to get that golden, crunchy topping. Enjoy!