Preheat the oven to 400°F.
Spray a baking dish with non-stick cooking spray.
Lightly brush the fish with the olive oil or melted butter.
Mix together the rest of the ingredients, except the panko, to make a paste. Spread half on each fillet. Press half of the panko on evenly on top of each fillet.
Bake for about 10 minutes, just until fish is opaque.
Turn on the broiler and finish for 2 minutes, until panko is golden brown and mayonnaise has puffed a little.