Begin by heating 2 tablespoons of vegetable oil in a large pan over medium heat. Add 2 minced garlic cloves, 1 tablespoon of freshly grated ginger, and 1 finely chopped green chili. Sauté for about 1 minute, stirring continuously, until the mixture is fragrant and the garlic begins to turn golden.

Next, add 2 sliced onions to the pan, stirring well to combine. Cook for approximately 3-4 minutes, until the onions become soft and caramelized to a golden-brown hue.

Once the onions are ready, stir in 1 teaspoon of turmeric, 1 teaspoon of chili powder, 1 teaspoon of ground cumin, 1 teaspoon of ground coriander, and 1 teaspoon of garam masala. Cook for another minute, allowing the spices to toast and release their aromatic flavors.

Add 2 chopped tomatoes and a splash of water, stirring to combine with the seasoned onion mixture. Season with salt to taste, then cover and let it simmer on low heat for around 10-12 minutes.

Introduce 500 grams of diced chicken thighs into the pan, ensuring they are well coated with the sauce. Increase the heat to medium and cook for 20 minutes, stirring occasionally, until the chicken is tender.

Lastly, stir in the juice of half a fresh lemon and garnish with fresh coriander leaves before serving.