In a large skillet, heat olive oil and butter over medium heat. Add minced garlic and red pepper flakes. Sauté for about 1 minute until garlic is fragrant.

Add chopped asparagus to the skillet, seasoning with salt and pepper. Sauté for 8–10 minutes until asparagus is bright green and crisp-tender.

Bring a pot of salted water to a boil. Add the pasta and cook according to package instructions until al dente, about 8–10 minutes. Reserve a cup of pasta water, then drain.

Lower heat and stir in Parmesan cheese until melted. Add drained pasta, tossing to combine. If dry, add reserved pasta water gradually.

Serve immediately, garnishing with additional Parmesan cheese and red pepper flakes if desired.