Vegetable Chili With Polenta

Name: Vegetable Chili With Polenta
Ingredients: 3 tablespoons olive oil; 1 large onion, finely chopped; 2 garlic cloves, minced; 2 tablespoons chili powder; 1 1/2 teaspoons ground cumin; 1 14.5-ounce can diced tomatoes with juice; 1 15.5-ounce can red kidney beans, drained and rinsed; 1 15.5-ounce can cannellini or great Northern beans, drained and rinsed; 1 tablespoon red wine vinegar; kosher salt and black pepper; 1/2 cup quick-cooking polenta; 1 tablespoon butter; green chili or jalapeño salsa, optional