Broccoli, Cauliflower & Brussel Sprout Gratin

This lusciously cheesy Broccoli Cauliflower Brussels Sprout Gratin isn’t your average casserole… it’s next level!!


1 lb cauliflower florets
8 oz broccoli
8 oz brussels sprouts (quartered)
2 cups onion (white or yellow)
1 tsp olive oil or butter
1/4 cup butter
1/4 cup flour
1/2 cup heavy cream (room temperature)
1 cup milk (room temperature)
4 oz freshly grated gruyere cheese
4 oz freshly grated gouda cheese
1/4 tsp salt
black pepper to taste
1/4-1/2 cup Italian-seasoned breadcrumbs
1-2 TBSP butter



Pre-heat oven to 350 degrees F.

Chop your veggies.
Bring a pot of water to boil and blanch broccoli, cauliflower, and brussels sprouts until the broccoli turns vibrantly green and all three veggies are somewhere between al-dente and fork-tender. This will take a few minutes, but no longer than 8. When your perfect texture is reached, shock the veggies in an ice bath (more info here) to halt the cooking process. No mushy veggies here! Alternatively if you’d prefer softer veggies, feel free to let them cook a smidge longer and/or skip the ice bath.

Place veggies in a casserole dish and set aside.

Drizzle a medium pot (one deep enough to make your cheese sauce in) with a little bit of olive oil or butter and caramelize your onions, stirring occasionally. Continue cooking until onions are golden brown and tender.

Turn your burner to medium-low heat and add 1/4 cup (4 TBSP) butter.
Once your butter has melted, slowly mix in flour a tablespoon at a time, whisking the mixture together as you go.

Once your roux has begun to form a paste with the onions, add room temperature (or slightly warmed) milk and cream, whisking constantly until the sauce thickens.
Remove your pot from heat (it will begin to thicken even further at this part) and slowly add 1/2 the cheese.

Pour sauce over veggies, then top with the cheese you set aside earlier.
Next melt 1 TBSP of butter in a small skillet and add breadcrumbs. Mix constantly while toasting, then sprinkle over casserole.
Bake on centre rack at 350 for 20 mins.

Recipe from Peas and Crayons