Cook gluten-free pasta according to box instructions, being sure to reserve 1 cup pasta cooking water before draining.
While the pasta cooks, melt 2 tbsp vegan butter in a large saute pan over medium heat.
Add ground pepper and use a spatula to mix into vegan butter, allowing the pepper to toast and incorporate into the melted butter, about 1 minute.
Carefully add about 1/2 cup of the reserved pasta cooking water and the salt to the butter mixture, then stir to combine.
Allow to simmer for about 2 minutes, then add remaining 1 tbsp vegan butter and allow to melt.
Add 3/4 cup of the grated vegan parmesan, stirring until a creamy sauce forms.
Immediately add drained, cooked pasta to the pot with the sauce and toss with tongs or two forks until noodles are coated with the peppery sauce.
Serve immediately, topping plates with remaining grated vegan parmesan at the table.