Preheat your oven to 425°F (220°C).
Toss the quartered Brussels sprouts with olive oil, salt, and pepper in a large bowl until evenly coated. Spread them in a single layer on a baking sheet.
Roast the sprouts for 15 minutes, or until they’re tender with lightly browned edges.
While the sprouts roast, toast the hazelnuts in a dry skillet over medium-low heat. Stir frequently for about 5 minutes, or until they’re golden and fragrant. Set aside.
Using the same skillet, cook the chopped bacon over medium heat until crisp, about 10 minutes.
Add the maple syrup and rosemary to the bacon. Continue cooking and stirring for another 5-8 minutes, allowing the mixture to thicken slightly.
Once the Brussels sprouts are done, toss them with the bacon mixture in a large serving bowl.
Sprinkle in the toasted hazelnuts, dried cranberries, and grated Pecorino-Romano cheese. Toss well to combine. Serve warm and enjoy!