Ingredients

• 1 pound penne pasta
• 2 tablespoons olive oil (plus more for tossing with the pasta)
• 1 head cauliflower (about 2 pounds total)
• 1 head broccoli (about 1 pound total)
• 1 small red onion, finely chopped
• For the cheese sauce:
• 1 1/2 tablespoons butter
• 1 1/2 tablespoons flour
• 2 cups milk
• 1/2 cup grated gruyere or sharp cheddar cheese

Serves 4 to 6 as a main