Wash, cut ends off, and slice brussels sprouts in half lengthwise. Put them in a bowl.
Pour 2 tbsp olive oil, 1/2 tsp salt, 1/4 tsp pepper and chili powder on top and toss together. Preheat your oven to 450 degrees
Put foil on a baking sheet and pour tossed brussels on pan, spread out so none are overlapping.
Bake for 10 minutes, then use a spoon or spatula to flip them over and bake again for another 8 minutes. (until lightly browned on top and tender)
Whisk together the last 7 ingredients to make your sauce. Pour baked brussel sprouts in this bowl and toss gently with sauce so all of them are coated.
Pour into a serving bowl, spoon remaining sauce left in bowl on top of the entire bowl of brussels. Can sprinkle some parmesan cheese on top as well, can squeeze 1/2 fresh lemon juice on top of brussels if desired.