Preheat oven to 425°F (218°C). Line a large rimmed baking sheet with parchment or foil for easy cleanup.

Trim and halve Brussels sprouts. Remove any yellow outer leaves.

Cook bacon in a skillet until crispy. Reserve 2 Tbsp bacon fat. Crumble bacon and set aside.

Melt 2 Tbsp butter with reserved bacon fat. Toss Brussels sprouts in this mixture with salt, pepper, and red pepper flakes.

Spread sprouts cut-side down on the baking sheet. Do NOT crowd — use two sheets if needed.

Roast 20–25 minutes, flipping once halfway, until deeply caramelized and crispy on the edges.

While roasting, make the glaze: Melt remaining 2 Tbsp butter with maple syrup, brown sugar, and minced garlic over low heat until sugar dissolves (2–3 minutes).

Remove sprouts from oven. Immediately toss with crumbled bacon and warm maple glaze.

Transfer to serving dish. Shower with Parmesan and optional balsamic drizzle. Serve hot!