Step 1

In a large pot, cook the onions in oil over medium-low heat for 10 to 15 minutes, until translucent. Add the garlic and cook for 1 more minute. Add the bell peppers, chili powder, cumin, red pepper flakes, cayenne and salt. Cook for 1 minute. Crush the tomatoes by hand or in batches in a food processor fitted with a steel blade (pulse 6 to 8 times.) Add to the pot with the basil. Bring to a boil, then reduce the heat and simmer, uncovered, for 30 minutes, stirring occasionally.

Step 2

Add the cooked chicken to the chili and simmer, uncovered, for another 20 minutes.

Step 3

Serve with the toppings, or refrigerate and reheat gently before serving.