Preheat the oven to 400°F. Line a rimmed baking sheet with heatproof parchment paper for easy cleanup.
Make the sauce: In a small bowl, mix the oil, soy sauce, honey, garlic, and red pepper flakes.
Place the Brussels sprouts in the pan and toss them with the sauce.
Arrange the seasoned Brussels sprouts, cut side down, in a single layer on the baking sheet.
Roast them, undisturbed, until browned and caramelized, for about 30 minutes.
Taste and decide if you'd like to sprinkle the dish with kosher salt. To my palate, the soy sauce makes it salty enough.
Garnish with sesame seeds and serve.
