01 - Preheat the oven to 425°F and line a baking sheet with parchment paper.
02 - In a large bowl, combine Brussels sprouts and red onion with olive oil, sea salt, black pepper, smoked paprika, and minced garlic; toss until evenly coated.
03 - Spread the seasoned Brussels sprouts and onions in a single layer on the prepared baking sheet.
04 - Roast in the preheated oven for 20 to 25 minutes, stirring once halfway through, until edges are golden and Brussels sprouts are crisp.
05 - Remove from oven and immediately toss with lemon zest, chopped fresh parsley, and toasted almonds if using.
06 - Transfer to a serving dish and enjoy warm as a vibrant side dish.