Cook the pasta according to package instructions. When finished, drain and rinse with cold water. Set aside.
8 ounces fettuccine
In a clean skillet over medium heat, melt the butter. Add the minced garlic and cook until fragrant, about 30 seconds, being careful not to burn it.
2 tablespoons unsalted butter, 2 cloves garlic
Whisk in the flour. Very slowly, whisk in the half and half. You want to just whisk in a small bit at a time, so that you can create a roux. I like to eyeball about 2 tablespoons at a time, only adding more half and half after what you just added is absorbed, going quicker the more you add.
1 tablespoon all-purpose flour, 1 1/2 cups half and half
Once you have whisked in all of the half and half bring the dish to a low simmer. Stir in the Parmesan cheese, melting it to combine. Then stir in the tarragon, lemon zest, kosher salt, and black pepper. Taste and adjust seasonings as needed.
1/3 cup Parmesan cheese, 1 teaspoon dried tarragon, 1 teaspoon lemon zest, 1/2 teaspoon kosher salt, dash freshly ground black pepper
Stir in the pasta and lump crab meat. Add a splash more half and half if it is too thick. Top with fresh parsley and enjoy.
8 ounces lump crab meat, fresh parsley for topping