Preheat oven to 375°F with rack in upper third. Line a baking sheet with parchment paper.
Wash and pat the salmon fillet dry, remove scales or pin bones. Place skin side up on the baking sheet.
Whisk together all glaze ingredients except butter and cornstarch. Reserve ⅓ of the marinade and pour the remaining into a saucepan.
Pour the reserved ⅓ marinade onto the baking sheet, lifting the salmon to get marinade under it. Set aside.
Add butter to the saucepan and bring to a boil. Reduce to a low boil until thickened. For a thicker glaze, mix cornstarch with 1 tablespoon water and stir into glaze; raise heat and stir until thick. Transfer to a bowl.
Place salmon skin side down on the prepared baking sheet. Season with salt, pepper, and paprika. Spoon some glaze over the top.
Bake at 375°F for 4-5 minutes. Glaze again, then switch oven to broil. Broil for 4 minutes until done to your liking (do not over bake).
Remove from oven, transfer to a platter, garnish with diced cilantro. Serve with rice, grains, or salad.