Preheat the oven to 180*C/350*F/ gas mark 4. Have ready a baking dish large enough to hold all of your fish in one layer with space in between each fillet. Spread one TBS of the melted butter on the bottom of the dish.
Wipe the fish dry and season it all over generously with salt and pepper. Lay in a single layer in the baking dish.
Combine the remaining butter and the cracker crumbs. Sprinkle these evenly over the fish.
Bake in the preheated oven for 15 minutes, until golden brown and the fish flakes easily. Serve hot with lemon wedges for squeezing and a sprinkle of fresh parsley if desired.