Heat the remaining 2 tablespoons of olive oil in the same skillet over medium heat. Add the onion, and season with salt and pepper. Cook, stirring occasionally, until tender and lightly browned, about 5-7 minutes. Stir in the garlic, ginger, and tomato paste. Cook, stirring, 1 minute. Sprinkle in the cumin, coriander, cinnamon and cayenne. Stir until fragrant. Pour in the chicken broth and give everything a good stir, scraping up any brown bits from the bottom of the skillet. Bring to a boil. Return the meat to the skillet, and reduce the heat to a simmer. Cook 5 minutes, or until thickened.