Step #1 TO MAKE THE LENTIL CAKES: Soak the dal overnight in 4 c of water, then drain off the water.
Step #2 Mix the drained dal with remaining lentil cake ingredients & whiz them in a mixer until you have a smooth creamy paste (add a little extra water to achieve this consistency if necessary).
Step #3 Heat just over half of the oil (from the curry sauce list of ingredients) In a large-ish frying pan (or karai); fry the lentil mixture over a medium heat until it leaves the side of the pan & a ball forms (sounds strange, but you’ll know it when you see it).
Step #4 Spread the lentil mix onto a greased plate, to a depth of ½ inch; leave this to cool & set.
Step #5 When set, cut the dal into 1 inch squares; then heat the rest of the oil in a frying pan over a medium high heat & fry the dal squares a few at a time, until golden brown; set aside.
Step #6 CURRY SAUCE: Fry the potatoes In a large-ish lidded frying pan until lightly browned; set aside.
Step #7 Lower the heat to medium & in the same pan add the cumin seeds & bay leaves, let them sizzle for a few seconds; add the turmeric, chilli, coriander, salt & tomatoes & fry for two mins; add water & bring to the boil.
Step #8 Add the potatoes, cover & cook for 10 mins then add the fried dal squares; cover again & cook this until the potatoes are tender (approximately 5-10 mins).
Step #9 Add the ghee, if using, & sprinkle on the garam masala; remove this from heat & serve hot.