Strain the all purpose flour salt, and baking powder into a bowl. Add yogurt and milk and knead it to form a dough. Add oil to the dough. Allow to ferment for 5 6 hours. Roll out and fry. For chole, chop the onion, ginger, garlic, tomato, coriander powder and salt. Use a blender to grind half of the chopped ingredients and half of boiled chickpeas. Heat oil in a pan. Add the cumin seeds. Then add the remaining chopped garlic ginger, onion and tomato with blended masala, red chilli powder, garam masala and chhole masala. Add some more boiled chickpeas and mix with water and salt. Stir well and cook for a few minutes. Garnish with the onion slices, lemon wedges, green chilli, and the coriander sprig. Serve hot.