1. Thoroughly season salmon fillets on all sides with salt and pepper.
2. Heat butter in a large cast iron skillet. Add the pieces of salmon to the skillet, skin side first, and cook for 2-4 minutes on each side – depending on thickness. For best results, use a fish turner to flip salmon. Remove from the skillet and set aside.
3. In the same skillet, melt remaining 2 tablespoons of butter. Add lemon juice, hot sauce, minced garlic, half the parsley, and red pepper flakes (if you want).
4. Add the zucchini noodles and cook for 3 or 4 minutes, stirring regularly to coat in the butter sauce, until zucchini noodles are done but still crisp and juices have reduced a bit. Adjust seasoning with salt and pepper and garnish with more parsley. Push zucchini noodles on the side and add salmon fillets back to the pan. Reheat for a couple of minutes. Serve immediately lemon garlic butter Salmon garnished with chopped scallion and a lemon slice on the side. Enjoy!
Note: Zucchini tends to render some water when cooking, so you can sprinkle with salt after spiralizing and allow to sit for a couple of minutes to drain off excess water. Rinse well to get rid of salt and drain thoroughly in a colander and pat dry before cooking.