In a large bowl, add the sliced onions, potatoes, spinach, fresh coriander, cumin seeds, cumin powder, coriander seeds, coriander powder, garam masala, turmeric, chilli powder, dried fenugreek leaves, garlic ginger paste, and fresh lemon juice. Mix well and set aside for 1 hour. During this time, the salt will draw water from the vegetables, reducing the amount of added water required; this increases the flavour of the finished pakoras.

After the pakora mix has rested for 1 hour, heat oil for deep frying to 170C/340F. If you're using a fryer with a basket, remove the basket before heating the oil as the pakoras will stick to the basket.

Add 2-3 tablespoons of water to the prepared pakora mix, then slowly add the gram flour and plain flour. Mix well and add a little more water and flour as necessary until the pakora mix has a slightly thick consistency and slides off the back of a spoon. Using two forks, carefully slide one forkful of pakora mix at a time into the hot oil.

Fry the pakoras in batches for 3-4 minutes, turning occasionally, until golden and crisp. Using a slotted spoon, lift the pakoras out of the oil and transfer to a plate. Leave to stand for 5 minutes, or if you prefer at this stage they can be set aside to cool completely, ready to fry again when you choose.

To finish the vegetable pakoras, heat oil for deep frying to 180C/350F. Carefully drop the pakoras into the hot oil and fry for 2 minutes until hot and crunchy. Use a slotted spoon to remove the pakoras from the oil, drain off any excess oil and arrange the pakoras on a serving plate. Garnish with thinly sliced onion and fresh coriander and serve with a lemon wedge.