Step 1

In a large pot of boiling salted water, cook the pasta al dente according to package instructions. Steam the broccoli on top of the pasta pot for 1-2 minutes, if possible. Drain the pasta well and blanch the broccoli.

Step 2

In another large saucepan over medium-high heat, melt the butter, then add the flour to make the roux. Whisk the flour and butter until they are combined and golden, about 2 minutes.

Step 3

Gradually whisk in the milk. Add the Dijon mustard and season with salt and pepper to taste. Bring the mixture to a boil, then reduce to low and simmer, occasionally whisking until sauce is thickened, about 5-7 minutes.

Step 4

Stir in the cheese, then fold in the pasta and broccoli. Serve immediately