Add oil to a Dutch oven or large heavy-bottomed pot over medium heat. Add the diced onion to the pot. Allow the onion to soften and caramelize until golden, stirring occasionally, about 15-20 minutes (you can go for longer if you want the onion to caramelize more deeply).

Add grated carrot, minced garlic and a big pinch of salt to the pot. Stir and sauté for 3-4 minutes, or until the carrot has softened and the garlic is aromatic. Add the tomato paste and stir until everything is coated, about 1 minute. Add the crushed tomato, tomato sauce, maple syrup, herbs and chili flake to the pot. Fill the empty 28-ounce can of crushed tomatoes with water and add that water to the pot. Taste and season with salt and pepper. Let the mixture come up to a simmer.

In a large bowl, combine the ground chicken, cooked rice and onion. I like to use a microplane to grate my garlic straight into the bowl. Add the salt, pepper and egg.

Combine everything until well incorporated, but make sure not to overmix or the meat can become tough. Clean hands work best for this. Before I cook the meatballs, I like to take a spoonful of the mixture and cook it in a small pan to taste for seasoning. I add more salt or pepper accordingly.

Form the ground meat mixture into even-sized balls. I prefer my tefteli slightly larger than a golf ball, but make them according to your own preferences. Drop the formed meatballs into the simmering sauce.

Make sure the sauce returns to a simmer, then lower the heat and partially cover the pot with a lid. Simmer the meatballs for 35-45 minutes or until cooked through. If you find the sauce is too thick, you can add more water. If you want the sauce less thick, you can simmer it for longer to reduce and thicken.