Use paper towels to thoroughly pat-dry excess moisture from fish fillets. This step is crucial for fish to brown nicely in pan – otherwise, it will steam instead of brown. Set aside.

In a bowl, combine melted butter, lemon juice and zest, and 1/4 tsp kosher salt. Stir to combine well. Taste and add a bit more kosher salt, if desired.

In a separate bowl, combine remaining 1/4 tsp kosher salt, paprika, garlic powder, onion powder, and black pepper. Evenly press spice mixture onto all sides of fish fillets.

In a large, heavy pan over medium high heat, heat up the olive oil until hot. Once your oil is sizzling, cook 2 fish fillets at a time to avoid overcrowding; this allows for even browning.

Cook each side just until fish becomes opaque, feels somewhat firm in the center, and is browned, about 2-3 minutes per side; lightly drizzle some of the lemon butter sauce as you cook, reserving the rest for serving. Take care not to over-cook, as that will result in a tougher texture. Season with extra kosher salt and freshly ground black pepper to taste.

If desired, season with extra kosher salt and freshly ground black pepper to taste.

Serve fish with with remaining lemon butter sauce, basil or parsley, and lemon wedges.