Bring a large pot of salted water to a boil. Cook the bucatini until al dente, following the package instructions. Reserve 1 cup of pasta water, then drain the pasta.

In a large pan over medium heat, melt the vegan butter. Stir in the salt and pepper, allowing their flavors to infuse into the butter.

Gradually add the nutritional yeast and miso paste to the pan, stirring until it forms a smooth, cheesy paste.

Add the drained pasta to the pan, tossing it gently to coat it in the sauce. Slowly pour in the reserved pasta water, a little at a time, stirring constantly until the sauce reaches your desired consistency.