Preheat the oven to 425 degrees F.
Wash the brussels sprouts well under running water. Pat dry completely with a clean kitchen napkin or paper towel.
Trim the ends of the brussels sprouts, discard the outer leaves or any other leaves that are yellow. Slice lengthwise.
Transfer the brussels sprouts to a sufficiently big bowl, add olive oil, salt, pepper, and crushed red pepper flakes. Toss to coat well. You may also add the outer leaves which fall while slicing the sprouts in half. They make for some delicious, crispy brussels sprouts chips.
Place the brussels sprouts on a rimmed baking sheet, cut side down in a single layer. Do not crowd the pan or stack them, they will steam instead of roasting and turn mushy. You may also line the baking sheet with aluminum foil for easier clean-up.
Roast for 20-25 minutes, shaking the sheet halfway through during roasting. If you like them really charred, turn on the broiler towards the end and broil for 1-2 minutes, keep a close eye or else they might burn.
Once the bottom of the Brussels sprouts has caramelized, remove the tray from the oven, transfer to a serving platter and drizzle the balsamic glaze all over the roasted brussels sprouts. Toss gently to combine and serve immediately, with some more maple balsamic glaze on the side.