Add shrimp to the skillet, seasoning with salt, pepper, and red pepper flakes if desired. Cook until shrimp are pink and cooked through, about 3-4 minutes.
Remove shrimp from the skillet and set aside.
In the same skillet, add zucchini noodles and cook for 2-3 minutes until tender but still crisp.
Add the cooked shrimp back to the skillet along with the remaining butter. Toss everything together until well combined.
Serve immediately, garnished with chopped parsley.
Notes
For added depth of flavor, consider marinating the shrimp in garlic and olive oil before cooking.