These Lentil-Walnut Vegetarian Meatballs are the perfect meatless meal. Serve them with spaghetti and your favorite tomato sauce for a hearty main.
In a large saucepan, heat the olive oil over medium. Add the onions, carrots, and celery and let cook for about 10 minutes (or until they begin to brown). Next, add in the garlic, oregano, and a little bit of salt. Let cook for another minute. Add tomato paste, stir, and cook for 3 more minutes.
Preheat oven to 400 degrees F and grease a 9x13-inch pan. Using clean hands, roll the mixture into golf ball size balls and place on greased baking sheet. Continue with the rest of the batter.