For this, I used a big, heavy-bottomed 12-inch skillet. That’s a grand size for frying the spiced pea mix, and then for cooking your aloo tikkis.
Add 2 tablespoons sunflower oil to your skillet and set it on a medium heat. Swirl the oil around so it coats the bottom of the skillet and then stir in the onions. There’s not a lot of oil here, so stir well so the onions get coated with it. (By only using that small amount of oil, you’ll stop your tikkis from being greasy.)
As soon as the onions are oil-coated, drop the heat to low-medium and stir fry the onions for about 3 minutes until they start to soften and begin to pick up a little pale golden color. Now stir in the garlic and ginger and keep stir frying on that low-medium heat for another 2 minutes or so. You want the onions to turn a little darker and just start to crisp a little around their edges.
Drop the heat to low and stir in the ground spices – cumin, cilantro, turmeric, cinnamon – and the black pepper.
Continue stir frying for another minute then add the fresh cilantro, serrano peppers, peas, and lemon juice. Give everything a thorough stirring and turn off the heat. Time now for a little crushing of the peas in the skillet.
Use a potato masher to crush the peas – in the skillet – so you get a roughly 50/50 mix of whole peas and crushed peas. That’s it. The spiced pea mix is done and ready to be mixed with the mashed potatoes.
Add all the spiced pea mix to your pan of mashed potatoes. Use a wooden spoon to slowly mix everything together. I say slowly because if you stir too vigorously, you’ll lose the coarse-ish texture of the potatoes and break up the peas more than you need to. Probably took me about two minutes to slowly get the lot mixed evenly together.