Aloo Tikka, Made in India

I bought Meera Sodha's book, Made in India and before I could even open it, one of my kids made some recipes out of it, including this one.  It is fantastic!

1 1/4 pound potatoes
1 tsp turmeric
1 tbsp neutral oil, plus extra to fry
1 red onion, finely chopped
2 tbsp grated fresh ginger
2 garlic cloves, peeled and crushed
1-2 medium green chillies, finely chopped
1 tsp black mustard seeds
½ tsp garam masala
1/3 c. shelled peas (frozen is fine)
3 tbsp fresh coriander, finely chopped
Juice of ½ lemon
4 tbsp semolina or cornmeal (or plain flour)
Knob of ghee or butter (optional)
Put the potatoes, whole and unpeeled, into a pan just big enough to hold them, along with the turmeric and a generous pinch of salt and cover with cold water. Bring to the boil, then simmer until very tender and drain. Put back into the hot pan for a minute or so to steam dry.
Meanwhile, heat the oil in a frying pan over a medium heat and then fry the onion until soft and beginning to caramelize. Stir in the ginger, garlic, chillis, mustard seeds and garam masala and fry for another minute. Stir in the peas and cook for a minute or so to defrost if necessary.
If you must, peel the potatoes, then mash well, and add to the frying pan. Stir in the lemon juice and two tablespoons of semolina, mix well then season to taste.
Roll the mixture into golf-ball sized portions, then flatten into cakes. Press both sides in semolina.
Coat the bottom of a frying pan with oil, and add the ghee if using. Heat over a medium-high flame, then add the tikki (they should sizzle). Cook until golden brown, then carefully flip over and repeat. Serve warm with chutney.