I always make this curry with sturdy veggies like cauliflower, potatoes, beans, carrots and green peas. That said, you can use any vegetables you have on hand. Simply be sure to add the vegetables in order of their cook times. Longer cooking vegetables (e.g. cauliflower and potatoes) should be added first, while fast cooking vegetables (e.g. spinach) should be added in the last few minutes.