Preheat your oven to 400°F (200°C) and line a baking sheet with parchment paper.
In a large bowl, toss the Brussels sprouts with olive oil, salt, and pepper until evenly coated.
Spread the Brussels sprouts in a single layer on the prepared baking sheet.
Roast in the preheated oven for 20-25 minutes, or until tender and caramelized, tossing halfway through for even cooking.
While the Brussels sprouts are roasting, heat a small skillet over medium heat and toast the breadcrumbs until golden brown. Set aside.
Once the Brussels sprouts are done, remove them from the oven and sprinkle minced garlic over them.
Sprinkle the grated Irish cheddar cheese and toasted breadcrumbs (if using) over the Brussels sprouts.
Return the baking sheet to the oven and bake for an additional 5 minutes, or until the cheese is melted and bubbly.
Serve the roasted Brussels sprouts with Irish cheddar cheese hot as a side dish or a satisfying snack.