Rinse the chicken thighs with water and pat dry with paper towels. Season with salt and black pepper on both sides of the chicken. Puree the tomatoes in a food processor.

Heat up a heavy bottom pot on high heat. When it's fully heated, arrange the chicken thighs, skin side down first. Brown both sides of the chicken. Remove the chicken from the pan, save juices from cooking chicken in the pan.

Turn the heat to medium and add the olive oil to the pan. Saute the onion and garlic, for a couple of minutes or until the diced onion becomes soft. Add the tomato puree and basil, stir to combine well. Transfer the chicken and the juice into the pot, cover the pot with its lid and simmer on low heat, for about 15-20 minutes, or until the chicken becomes tender. Add salt and brown sugar, stir to combine well. Garnish with chopped parsley and serve immediately.