In a gallon-sized zip-top bag, combine the freshly squeezed lemon juice, olive oil, paprika, garlic salt, and black pepper.
Add the halved or quartered Brussels sprouts to the bag. Seal tightly and shake well until all pieces are thoroughly coated with the marinade.
Place the bag in the refrigerator and allow the mixture to marinate overnight.
When ready to cook, preheat the oven to 400°F (200°C). Arrange the marinated Brussels sprouts in a single layer on a baking sheet.
Roast for 15 to 20 minutes, or until the edges are browned and crispy while the centers remain tender. Serve hot and enjoy immediately.