In a large pot of boiling salted water, cook pasta according to package instructions; drain well.

In a medium saucepan, combine butter, garlic and red pepper flakes over medium heat until the butter has melted. Cook, whisking constantly, until the foam subsides and the butter begins to turn a golden brown, about 4-5 minutes, skimming foam as necessary.

Remove from heat. Stir in pasta and Parmesan until well combined, about 2 minutes; season with salt and pepper, to taste.

Serve immediately, garnished with parsley, if desired.