In a bowl, mix 500 grams of boneless chicken pieces with 1 teaspoon ginger-garlic paste, 1 teaspoon red chili powder, 1/2 teaspoon turmeric powder, 1/2 teaspoon garam masala, salt to taste, and 2 tablespoons of yogurt. Marinate for 30 minutes.
In a pan, heat 2 tablespoons of oil and add 1 teaspoon cumin seeds. Once they start to crackle, add 1 finely chopped onion and sauté until golden brown.
Add the marinated chicken to the pan and cook on medium heat for 10-12 minutes, stirring occasionally.
In a separate bowl, mix the juice of 2 lemons, 1 teaspoon cornflour, and 1/4 cup of water. Pour this mixture over the chicken and cook for another 5-7 minutes until the sauce thickens.
Garnish with freshly chopped coriander leaves and serve hot with rice or roti.