Melt butter in a medium saucepan over medium heat, stirring frequently until melted and foam has subsided, about 3-4 minutes. Stir in garlic until fragrant, about 30 seconds.
Remove from heat; stir in lemon zest, lemon juice and parsley. Set aside.
Season fish with salt and pepper; to taste. Dredge fish in flour until evenly coated, shaking off excess flour.
Heat 2 tablespoons vegetable oil in a large nonstick skillet over medium high heat. Working in batches, add fish to the skillet in a single layer and cook until golden brown and cooked through, about 2-4 minutes per side.
Serve immediately, drizzled with butter and garnished with lemon wedges, if desired.
Notes
Salted butter goes a long way.Kerrygold salted butter will work very well here (along with any other European style butter) due to its higher fat content (82% vs 80% for standard butter), providing a richer, creamier, smoother emulsification for your butter sauce.
Pat dry. Pat the fish completely dry with paper towels to remove any surface moisture (moisture equals steam), allowing for a better sear and achieving a crispy, golden-brown crust.
Use a neutral oil. Skip the olive oil and use a neutral-flavored oil with a high smoke point such as vegetable oil or peanut oil for pan-frying the fish, yielding a crispy exterior without burning the fish.
Mix it up. Add additional garlic cloves or any other herbs on hand (basil, thyme, dill or rosemary), or even a teaspoon of Italian seasoning.
Cook in batches. Work in batches to properly pan-fry the fish for that favorited golden brown crust. An overcrowded pan will steam the fish instead.
Use fresh lemons. Fresh lemon juice is ideal here for its bright, vibrant, strong flavors, cutting through the richness of the butter, whereas bottled lemon juice may have a muted, flat taste.
Add a splash of white wine. If you happen to have an open bottle of wine, add a splash of wine to the sauce. It will cut through the richness and further balance the flavors, transforming the lemon butter sauce into restaurant-quality goodness. Pinot Grigio, Sauvignon Blanc, or unoaked Chardonnay are all solid options.
Let it rest. Let the fish rest for 5 minutes before serving, allowing the juices to redistribute.