Stir together melted butter, lemon juice, lemon zest, garlic, dill, and ½ teaspoon of salt in a small bowl. Set aside.
Blot haddock pieces with paper towel to remove excess moisture. Season with paprika, ½ tsp salt and cracked black pepper.
Heat olive oil over medium-high heat for 2 minutes in a large pan. Sear haddock on both sides for 2-3 minutes. Set fish aside on a plate and discard oil from pan.
Return pan to stove over medium low heat and add fish to pan. Spoon half of the butter sauce over halibut. Continue to cook until haddock is cooked through, about 3-4 minutes.
Warm butter sauce in a saucepan or microwave if butter begins to solidify. Serve haddock hot with remaining lemon butter sauce, fresh parsley and lemon slices.