Cut the steak into bite-sized pieces and season generously with salt and pepper.

Cook the pasta according to package instructions until al dente; then drain.

In a large skillet over medium-high heat, warm olive oil. Sear the steak bites in batches for about 3-4 minutes until browned on all sides.

Add minced garlic to the skillet and sauté for an additional minute until fragrant.

Combine the cooked pasta with pesto and steak in the skillet, mixing well. If needed, add reserved pasta water for creaminess.

Serve immediately, garnished with crushed red pepper flakes or parmesan cheese if desired.