Cook pasta according to package directions. Meanwhile, make the sauce.
In a large saucepan, add vegan butter and garlic over medium heat. Sauté garlic for 1-2 minutes, until butter is just melted.
Sprinkle flour into the pan and stir just until the flour is incorporated into the butter. Slowly add in the coconut milk and vegetable stock; use a whisk to stir away clumps and combine ingredients.
Whisk until the mixture comes to a low boil then starts to thicken a bit. Add two tablespoons of hot starchy pasta water (the water from the pot in which you cooked the pasta) and continue to stir continuously for another minute. The sauce will continue to thicken, so it shouldn't be super thick yet at this point, but it should be thicker than when you started stirring the liquid.
Remove from heat and immediately stir in Dijon mustard, 1 teaspoon of black pepper, and nutritional yeast flakes. Stir until the flakes have melted. Add the cooked pasta to the pan and gently toss together with the sauce, coating all of the pasta evenly.
Salt and pepper to taste. Garnish with freshly chopped parsley.