Most Punjabi dishes are prepared using "tadka", which is made with the frying of a "masala", which is a mix of ginger, garlic, onions and tomatoes with some dried spices. This is followed by the addition of other ingredients, water, and occasionally milk. Normally spicy, spice levels vary greatly depending on the household itself. Ghee and mustard oil are the most commonly used cooking fats. Many popular Punjabi dishes such as butter chicken and rajma are curry-based. These dishes are usually served with steamed rice and chapatis.