Preheat your oven to 400°F (200°C).
In a food processor, combine the cooked green lentils, rolled oats, chopped red onion, garlic, egg whites, cooked chickpeas, and nutritional yeast. Process until the mixture is mostly blended yet retains a bit of texture for a hearty bite.
Form the mixture into small, even meatballs, placing them on a lightly greased or parchment-lined baking sheet.
Bake the meatballs in the preheated oven for 20-25 minutes, or until they are firm and lightly browned. Turn them halfway through baking for even cooking.
While the meatballs bake, prepare the vegetables. Chop your selection of bell pepper, zucchini, and carrot into bite-sized pieces. Toss them in olive oil, salt, and pepper.
Spread the vegetables on a separate baking tray and roast in the oven for about 15-20 minutes until tender and slightly caramelized, stirring halfway.
Once both the meatballs and vegetables are ready, plate them together. Optionally, garnish with a sprinkle of fresh herbs or a dash of lemon juice for brightness.
Enjoy your hearty and nutritious meal!