Preheat your oven to 400°F (200°C).
Clean and trim the Brussels sprouts, then halve them.
Toss the halved sprouts with olive oil, minced garlic, salt, and pepper. Spread them out on a baking sheet.
Place the Brussels sprouts in the preheated oven and roast for approximately 20-25 minutes or until they become tender and develop a gentle golden brown hue.
While the sprouts are roasting, prepare the sauce. In a mixing bowl, whisk together mayonnaise, Dijon mustard, honey, and apple cider vinegar. Season with salt and pepper to taste.
Once the Brussels sprouts are done roasting, remove them from the oven and drizzle the prepared sauce over them.
Return the sprouts to the oven and broil for an additional 2-3 minutes until the sauce is bubbly and slightly caramelized.
Serve hot.