Clean and cook the brussels sprouts for about 5 minutes, drain, and set aside.
Preheat the oven to 425°F/220°C.
In a mixing bowl, combine the olive oil, honey, apple cider vinegar, chili flakes, salt and pepper. Mix to combine everything. Toss in the cooked brussels sprouts, carefully mix to coat the brussels sprouts, and make sure they are well coated with the hot honey marinade.
Dump the brussels sprouts onto a baking sheet lined with parchment paper and distribute in an even layer.
Bake for 15 to 20 minutes or until the brussels sprouts turn golden brown.
Remove from the heat, transfer to a serving dish, and top with the fresh parmesan cheese and the spring onions.