Combine soy sauce, brown sugar, rice vinegar, sesame oil, honey, ginger, garlic powder, and red pepper flakes if using in a small saucepan set over medium-high heat. Bring to a boil, then reduce heat to medium and let it bubble for 1-2 minutes.
1/2 cup low-sodium soy sauce, 1/4 cup packed light brown sugar, 2 Tablespoons rice vinegar, 1 Tablespoon toasted sesame oil, 1 Tablespoon honey, 3/4 teaspoon ground ginger, 1/2 teaspoon garlic powder, 1/8 teaspoon red pepper flakes
While the sauce is simmering, mix the cornstarch and cool water in a small bowl and stir into a thin slurry, then stir this into the soy sauce mixture. Keep bubbling until the sauce is thick enough to visibly coat the back of spoon. Set aside to cool for 5-10 minutes. (You can do this a few minutes or a few days ahead of time and store in the fridge.)
1 teaspoon cornstarch plus 1 teaspoon cool water
Place salmon in a large bowl and pour about half of the sauce on top, reserving the rest. Set aside to marinate for 15-20 minutes at room temperature or up to 24 hours in the refrigerator.
4 salmon fillets
When ready to bake, heat oven to 400 degrees F and line a rimmed baking sheet with parchment paper for easy clean-up. Place salmon fillets skin side down on the sheet. Discard the sauce that was used as a marinade. Roast salmon for 12-15 minutes, until it flakes easily with a fork and reaches 135-140 degrees F in the thickest part.
Make bowls of rice and top with salmon, edamame, carrots, cucumber, and avocado as desired. Drizzle the reserved teriyaki sauce generously on top.
2 cups cooked rice, 1 cup shelled edamame, 1 cup shredded carrots, 1 cup chopped cucumber, 1 avocado
Sprinkle with sesame seeds and green onions for an optional garnish, and dig in!
sliced green onions and sesame seeds