In a large mixing bowl, combine the ground beef, egg, breadcrumbs, garlic, oregano, salt, and pepper. Mix gently until just combined. Avoid overmixing because it can make the meatballs dense instead of tender.
Using your hands or a cookie scoop, form the mixture into evenly sized meatballs. Try to keep them similar in size so they cook evenly. Place them on a parchment-lined baking sheet.
Wash and cut the broccoli, carrots, and bell pepper into bite-sized pieces. Toss them with olive oil, garlic powder, salt, and pepper. Make sure every piece is lightly coated for even roasting.
Place the tray of meatballs into a preheated 400°F (200°C) oven. Bake for about 15–20 minutes until cooked through and lightly browned. The inside should no longer be pink.
Arrange the vegetables on a separate baking sheet or around the meatballs if space allows. Roast for about 20–25 minutes. Stir halfway through cooking to ensure even caramelization.
While the meatballs and vegetables cook, prepare rice or quinoa according to package directions. Fluff with a fork before serving. This creates the perfect foundation for the bowl.
Divide the rice or quinoa among four serving bowls. Top with roasted vegetables and juicy meatballs. Arrange everything neatly for an attractive presentation.
Finish each bowl with chopped parsley, a squeeze of lemon juice, or your favorite sauce. Serve immediately while everything is warm and fresh. Enjoy every flavorful bite.