1) Preheat the oven to 400°F.
2) Coat the bottom of a shallow baking pan with butter.
3) Place the fish in the baking dish and dredge it with salt and cayenne on both the sides.
4) Arrange alternating lemon and cucumber slices on top of the fish.
5) Bake the fish for 10 minutes or until tender.
6) Carefully place the fish on the serving plate with a lemon wedge on side and garnished with chopped parsley if desired.