We're just entering courgette glut season; if you're not growing them yourself, ask any gardener if s/he wants to get rid of a load! This
recipe, with occasional variations from the basic ingredients and instructions, is a regular in this household, in fact I'm making it today. As noted, the "meatballs" freeze well.
The book this is copied from, Madhur Jaffrey's "Eastern Vegetarian Cooking" is worth looking out for - it may be out of print; it's possible you'll find one in a charity shop, but unlikely, as it's one that people seem to hang on to, for some reason.
Edited: whatever recipes you choose to follow, always buy whole spices, preferably from an Indian shop, and grind them just before use, if the recipe calls for ground spices. Learn the Indian names for spices - they won't always be labelled with an anglicised name!