01 - Preheat the oven to 425°F. Line a baking sheet with parchment paper.
02 - In a large bowl, toss the Brussels sprouts and red onion with olive oil, salt, pepper, and smoked paprika until evenly coated.
03 - Spread the vegetables evenly on the prepared baking sheet. Scatter beef bacon pieces over the top.
04 - Roast in the oven for 20 to 25 minutes, stirring halfway through, until the Brussels sprouts are golden and the bacon is crisp.
05 - Transfer to a serving dish, garnish with parsley and Parmesan if desired. Serve hot.