Meatless Monday: Butternut Squash and Rapini Casserole

Its Meatless Monday again! This recipe is inspired by some of my favorite ingredients and one of my favorite chefs. I was binge watching A Chef’s Life (its so good, y’all) and saw chef Vivian Howard make a really tasty looking butternut squash, rapini, and sausage casserole. You know someone’s a culinary badass when they make the lowly casserole look sexy.

This got me thinking of ways I could make my own fancy pants casserole using a similar flavor profile. And so, the Rapini and Butternut Squash casserole was born! The bitterness of the rapini does a wonderful job of balancing out the sweetness of the squash and the richness of the mornay (a.k.a. cheese) sauce. Unlike Ms. Vivian, I chose to forgo sausage in my casserole to make this a decadent edition to my Meatless Monday series. Enjoy!

Butternut Squash and Rapini Casserole, serves 4-6 depending on if it’s a main dish or a side


  • 1 butternut squash cut into 1” cubes (mine yielded about 2 quarts)
  • 2 bunches of Rapini (Broccoli Rabe), large stems removed
  • 2 cloves crushed garlic
  • ½ Cup grated parmesan
  • ¼ teaspoon Red pepper flakes
  • ½ Lemon, zested
  • 1 cup whole Milk
  • 2 Tablespoons Butter
  • 2 Tablespoons Flour
  • 1 tablespoon olive oil
  • salt and pepper to taste
  • ½ teaspoon finely chopped fresh rosemary
  • ½ teaspoon finely chopped fresh sage
  • 1/3 -1/2 cups panko bread crumbs for topping


  • 8”x 8” oven proof casserole dish, greased with butter or oil
  • wooden spoon
  • 1 whisk
  • 1 small sauce pan
  • 1 slightly larger sauce pan
  • for blanching: pot of boiling salted water and bowl of ice water
  • 9”x13” baking sheet lined with foil and sprayed with a non-stick cooking spray or olive oil

The Process:

Squeeze excess moisture out using a kitchen towel

1) In a pot of boiling water, blanche your rapini greens for about 2 minutes. Remove the greens from the hot water and place in an ice bath to cool. This helps cook them, while allowing them to retain their sharp green color. When the greens have cooled, drain them thoroughly and squeeze out any excess moisture. Otherwise, you will have one soggy casserole. You can do this up to a day before. Just store the greens in a Tupperware in the fridge.

2) Next, Roast the butternut squash: Toss your squash with 1 tablespoon olive oil and a large pinch of salt and pepper. Place on your baking sheet and roast for 30 minutes at 425 degrees until slightly tender and golden brown. Precooking the squash will help reduce moisture and cook time when you finally bake your casserole. This step can also be done up to a day before casserole assembly. Just store your squash (after its completely cooled) in the fridge.

Making your roux is the first step to a mornay or beschamel sauce

3) On the day of assembly, butter or grease a casserole dish. Set aside

4) Preheat your oven for 375 degrees.

5) Make your mornay sauce a.k.a. cheese sauce. Begin by warming up your milk in a small sauce pan over medium low heat along with sage, rosemary, and red pepper flakes.  Be careful not to scald your milk. This means do not boil it. Funky stuff will happen if you do.

After the roux cooks, add your milk and any seasonings

6) while your milk warms up, melt your butter and sauté your garlic in a larger sauce pan over medium heat for about 1 minute. Add your flour. Stir continuously   using a wooden spoon or whisk over medium low heat until a paste forms. This is called a roux. Cook your roux over medium low heat for about 2 minutes to cook the flour taste out of it.

7) Add your warm milk to your roux. Whisk the milk and roux continuously for a couple of minutes until the milk has thickened to the consistency of a thin gravy. To see if your mornay/béchamel has thickened enough do the wooden spoon test. Dip a wooden spoon into the sauce. Drag your finger over the the back of the spoon. to create a line (it should look like the sauce version of Moses parting the red sea. Sauce on either side of a strip of exposed wooden spoon). If the sauce on either side begins to come back together, then its too thin. If the line maintains its shape, then your sauce is perfect.

If you can drag your finger through the sauce and it stays separated, you know its done.

Troubleshooting Your Sauce:

Sauce too Thin: Just cook it longer whisking it continuously until it thickens. Also you can just add more cheese at the end. Do not just dump more raw flour into it. This can create lumps.

Sauce too thick: Whisk in a little more milk until your sauce has reached your desired consistency.

Sauce too Lumpy: This would happen if you dumped raw flour into a piping hot liquid. Just pour your sauce through a fine metal sieve.

8) Turn the heat off under your sauce. Add the parmesan cheese and lemon zest. Taste for seasoning and season with salt and pepper as needed (since the parmesan is a salty cheese, don’t season the sauce until after you’ve added the cheese)

Last step to a good mornay is adding your cheese

9) Now that your mornay sauce is done, you can assemble your casserole. In your casserole dish, mix together the mornay sauce, the rapini, and the butternut squash. You can do this  a few hours ahead of time or even the night before. Just place plastic wrap directly on top of the surface of the casserole mixture and store in the refrigerator. This prevents a creepy dairy based skin forming over the top.

10) Sprinkle the top of your casserole with panko bread crumbs and any leftover parmesan.

Casserole is assembled and ready to be topped with bread crumbs and cheese.

11) Bake your casserole for about 20 minutes or until the casserole is heated through and the top is golden brown (if you want a more golden crust, you can put your casserole under the broiler for a minute or two. Watch it carefully to make sure it doesn’t burn).

12) When the casserole is done, take it out of the oven. To make it extra fancy, you can top it with fresh chopped parsley. Or not. Let the casserole cool for a few minutes and then serve.

Golden brown and ready to eat!

C and S note: Though this casserole is vegetarian, you could easily make this omnivore friendly by adding shredded rotisserie chicken or cooked Italian sausage to the casserole mix.

Disclaimer: I received nothing for this post. Insert sad face.

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