1. Put the potatoes in a large saucepan and cover with cold water. Bring to the boil then cook for 15 minutes until very tender. Remove with a slotted spoon and transfer to a colander to steam dry. Add the peas to the water and cook for 3 mins. Drain well.
2. Meanwhile, combine the spices with plenty of seasoning. Use a fork to lightly crush the peas then stir in half of the spice mix for punch and half of the butter or ghee. Mash the potatoes well with the remaining spice mix, butter, flour and seasoning then set aside to cool to room temperature.
3. Combine all the ingredients for the salad and set aside. Make the raita: grate the cucumber then sprinkle over a little salt and set aside for 5 mins. Squeeze out the excess water with your hands then stir into the creamy yogurt, along with the garlic, mint and lemon juice for zing. Season to taste and set aside.
4. When the potato mixture is cool, use slightly wet hands to shape into 12 flat patties in the palm of your hand. Take a heaped teaspoonful of the peas and place in the middle, then carefully wrap the potato around the peas to encase them. Shape into rounds about 1.5cm thick. Dust all over with the remaining 1 tablespoon of flour, shaking off any excess.
5. Heat 1 tablespoon of the oil in a non-stick frying pan and cook the cakes three at a time for 3 mins on each side until golden. Transfer to a lined baking tray and keep warm in a low oven while you repeat with the remaining oil and potato cakes.
6. Stack the potato cakes with the salad and serve with the raita for dipping.