Ghugni chaat is a popular street food in northern and eastern parts of India. Serve it as a filling for this tart along with homemade plum chutney (any leftover chutney is delicious with cheese or a curry).
Make the pastry. Mix both flours, along with the salt, turmeric, carom seeds and chilli powder in a bowl. Rub in the shortening until the mixture forms fine crumbs, then add the water a little at a time to form a dough.
Divide the dough into 4 equal pieces. On a lightly floured worktop, roll out each piece to a circle about 14cm in diameter. Place 1 dough circle into each tart tin and press it into the base and fluted sides. Trim the edges, then chill the cases for 10 minutes.
Make the chutney. Put the plum pieces into a medium pan over a medium heat. Add the sugar and cook for 10 minutes, until the plums have fallen to a pulp. Add the five spice and the ginger, increase the heat to medium–high and cook, uncovered, for 5 minutes, stirring occasionally, until the chutney is thick and most of the liquid has evaporated. Set aside to cool.
Heat the oven to 200°C/180°C fan/400° F/Gas 6. Line the chilled pastry cases with tin foil squares, then fill them with baking beans. Bake blind for about 10 minutes, then remove the baking beans and foil. Bake for a further 5 minutes, then remove from the oven and set aside (leave the oven on).
Make the filling. Split the cardamom pods to get the seeds (discard the skins). Put the cardamom seeds, chilli skins, coriander seeds, cumin seeds, and cassia or bay leaves into a small pan and toast over a medium heat for 1–2 minutes, until just toasted. Place in a spice grinder or mortar, and grind to a powder. Set aside.
Cook the potato in boiling salted water for 3–4 minutes, then drain. Heat the oil in a medium pan over a medium heat. Add the onion and fry for 5 minutes, until translucent.
Add the garlic, ginger and chat masala to the onion, along with the prepared spice mixture, and cook for 1 minute. Add the chopped tomato, chickpeas and cooked potato.
Lower the heat and cook for 5 minutes more, then taste and season with salt. Crush half of the chickpeas with the back of a spoon to break them up. Stir in the lemon juice.
Spoon 1 tablespoon of the chutney into each pastry case, divide the filling equally over the top of the chutney and drizzle with yogurt. Bake for 5 minutes to warm through.
To make the raita, mix the cucumber, radish and onion with the yogurt and season with salt, lemon juice and chat masala. Serve with the tarts.