In a mortar and pestle, add garlic cloves, red chilli powder, cumin seeds, coriander powder, and salt. Crush to a coarse paste. Set aside. A small grinder works if you pulse briefly. You want texture, not a smooth purée.

Heat ghee in a pan over medium heat. Add cashews and roast, stirring often, until lightly golden and fragrant, about 3–4 minutes. Transfer to a plate.

In the same pan, heat oil. Add hing and cumin seeds. Let them sizzle for 30 seconds.

Add ginger paste and green chillies. Cook until the raw ginger smell fades, about 1 minute.

Add onion and cook until translucent, 3–4 minutes.

Stir in the garlic chutney, turmeric, coriander powder, and red chilli powder. Fry the masala in the oil for 1–2 minutes. This step gives the dhaba depth.

Add tomato purée and cook until the oil separates at the edges and the raw tomato smell is gone, about 5–6 minutes on medium heat.

Lower the heat. Add buttermilk, water, salt, and sugar. Stir continuously as the gravy comes to a gentle boil. This prevents the buttermilk from splitting.

Add the roasted cashews. Cover and simmer on low for 5 minutes so the kaju absorbs the gravy and softens.

Stir in garam masala and half the coriander leaves. Taste and adjust salt or sugar if needed. The gravy should be pourable, not thick like a restaurant curry.

Just before serving, crush the gathiya lightly with your hands into bite-size pieces and stir into the shaak. Serve immediately with roti, paratha, or methi thepla. Do not simmer after adding gathiya. It goes soft within minutes.