Preheat oven to 425F and line a baking sheet with parchment paper.
Fill a large pot with water and salt generously (about 3-4 quarts water, about 2 tablespoons salt). Bring to a boil, then cook the pasta according to the package instructions. Reserve about 1 cup pasta water, then drain.
Add the brussels to the baking sheet and drizzle with oil, salt, and pepper and toss to coat. Add the bacon bits and toss to combine, then spread out into an even layer. Bake for 25-30 minutes, or until the bacon is cooked and brussels are tender and nicely charred.
Add pasta back to the pot along with the brussels/bacon. Add about ½ cup pasta water and ½ cup parmesan cheese and toss/stir to combine until that pasta drinks up that pasta water and the cheese, about 1 minute. You can always add more pasta water if it looks a bit dry.
Serve topped with remaining parmesan and black pepper.