1-First, cook the fettuccine pasta in boiling salted water until it’s al dente, which usually takes about 8-10 minutes. Be sure to reserve half a cup of the pasta water before draining, as it helps thicken the sauce later.

2-Next, in a large pan over medium heat, cook the 2 pounds of ground hot Italian sausage with the diced onion until the sausage is no longer pink and the onions are soft. This takes around 5-7 minutes and adds a rich base to your dish.

3-Season the mixture with 1 teaspoon garlic powder, 1 teaspoon seasoning blend, 1 teaspoon black pepper, 1/2 teaspoon red pepper flakes, 1 teaspoon oregano, and 1 teaspoon basil. Stir in the two 15-ounce cans of tomato sauce and the 12-ounce can of tomato paste, then let it simmer for about 10 minutes to blend the flavors.

4-For the creamy white sauce, melt 1/2 cup of butter in another pan and whisk in 1 tablespoon of all-purpose flour to make a roux. Gradually add 2 cups of heavy cream, stirring constantly to avoid lumps, then mix in 6 ounces of shredded Parmesan cheese, salt, pepper, and the reserved pasta water.

5-Combine the cooked pasta with the white sauce until it’s evenly coated. Pour this mixture into a baking dish, top it with the sausage tomato sauce, and sprinkle on 2 1/2 cups of shredded mozzarella cheese. Bake uncovered at 350°F (175°C) for 20 minutes until the cheese is melted and bubbly.

6-Serve it hot with a side salad and garlic bread for a complete meal. Remember, tips like stirring the roux continuously and cooking pasta al dente keep everything perfect. Total prep time is about 30 minutes, with 20 minutes of cooking.