Heat 2 tbsp oil in large Dutch oven or skillet over medium-high heat. Add chicken in batches of two or three so you don't overcrowd the pan. Cook until browned on each side, about 3 minutes per side. Remove chicken and set aside.
Reduce heat to medium and remaining oil. Add the onions and cook for 4-5 minutes or until translucent. Add the ginger, garlic and jalapeño and cook for another minute.
Add the chili powder, cumin, coriander, cardamom, garam masala, salt and black pepper. Cook for about a minute. Add in the tomatoes, tomato paste and water and bring to a boil. Reduce heat to simmer for 5 minutes.
Add chicken back to skillet and simmer for 15 minutes, or until the sauce is slightly reduced. Garnish with some cilantro and lemon juice.
