Preheat oven to 400°F. Line a sheet pan with parchment paper or grease with nonstick spray.
Toss the broccoli, asparagus, mushrooms and leeks with the olive oil and salt and pepper. Spread into an even layer on the sheet pan and roast until fork tender, stirring a few times as needed, 25-30 minutes.
Meanwhile, bring a pot of salted water to a boil. Add fettuccine and cook until al dente. Drain, reserving 1 cup of pasta water.
While the pasta is cooking, melt the butter in a large skillet. Add the heavy cream and half of the cheese and stir until smooth. Season with salt and pepper to taste.
Add the drained pasta and toss until coated in the sauce. If the sauce is too thick, add some pasta a little at a time until it loosens up.
Add the roasted vegetables and remaining cheese and toss until combined.
Serve immediately.
Calories: 1186kcal, Carbohydrates: 94g, Protein: 40g, Fat: 74g, Saturated Fat: 39g, Cholesterol: 272mg, Sodium: 1073mg, Potassium: 839mg, Fiber: 7g, Sugar: 6g, Vitamin A: 3205IU, Vitamin C: 48mg, Calcium: 728mg, Iron: 5mg