In a glass baking dish or large resealable plastic bag, combine the soy sauce, honey, garlic, ginger, and pepper flakes (if using). Add the salmon, skin-side up. Cover and refrigerate for 30 minutes.
Heat broiler on high. Transfer the salmon to a foil-lined broiler pan, skin-side down. Broil until the salmon is the same color throughout and flakes easily, 7 to 10 minutes. If desired, pour the marinade into a small saucepan and boil for 1 minute. Spoon the sauce over the salmon.
Tip: Consider this recipe a basic outline for teriyaki sauce that you can tweak according to your family’s preferences. Try using chicken in place of the salmon, swapping pineapple juice for the honey, or skipping the red pepper flakes if your kids have an aversion to all things spicy.