Begin by boiling a large pot of salted water over high heat. Add the fettuccine pasta and cook according to the package instructions, typically around 8-10 minutes, until al dente. Once cooked, drain the pasta, reserving a little pasta water, then set it aside in a large bowl.

In a large skillet, melt 4 tablespoons of butter over medium heat. Once melted, whisk in 1/4 cup of all-purpose flour, cooking for about 1 minute until bubbly and golden.

Slowly pour in 2 cups of whole milk while continuously whisking to prevent lumps. Cook the mixture over medium heat until it thickens slightly, about 3-4 minutes.

Add 4 ounces of cream cheese to the thickened sauce, stirring gently until fully melted and incorporated.

Stir in 1 cup of grated Parmesan cheese along with 1/2 teaspoon garlic powder, 1/2 teaspoon onion powder, and salt and pepper to taste.

Gently fold in 8 ounces of lump crabmeat, cooking for an additional 2-3 minutes until the crab is heated through.

Finally, add the drained fettuccine pasta to the skillet, tossing it gently with the sauce. If the sauce seems too thick, splash in a bit of the reserved pasta water.

Garnish generously with freshly chopped parsley and serve immediately.