Cut 1 lemon into 8 wedges. Grate rind of remaining lemon to measure 1 teaspoon; set aside. Reserve second lemon for another use.
Combine salt, paprika and pepper; sprinkle over fish. Arrange fish and lemon wedges on a rimmmed baking sheet coated with cooking spray (I cover the sheet with foil then spray for easy clean-up). Bake at 425 degrees for 13 minutes or until fish flakes easily when tested with a fork or until desired degree of doneness.
While fish bakes, combine 1 teaspoon grated rind, butter and 1 1/2 teaspoons of fresh thyme in a small bowl.
Place fish on individual serving plates; top each fillet with herb butter. Garnish with lemon wedges and chopped fresh thyme, if desired.