For additional flavor/extra color, sauté 1 cup diced bell pepper (red, green and yellow) along with onions and garlic. When cooled, fold them into the mixture. Another option - add 1/4 shredded fresh basil and 1/4 cup grated Pecorino Romano cheese. The simplest flavor change would be to add 1 tbsp of fresh herbs, such as thyme or rosemary.