Cook the Book: Pure and Simple
Note: This cookbook does use dairy products and is centered around northern cuisine
Pure & Simple : Homemade Indian Vegetarian Cuisine provides lots of ideas for easy to make vegetarian dishes. While you'll want to make sure you have indian ingredients like asafoetida and chickpea flour on hand for many of the dishes, there are some common ingredient recipes as well with tomatoes, potato, etc. There is a list of local ethnic grocery stores on Arborwiki if you have difficulty finding some of the ingredients.
While simple and little work, a potato/tomato dish had plenty of flavor with a myriad of spices (I found I needed to add more than directed for my taste level):
A more elaborate dish was a chickpea flour dumplings (pictured above) in a spicy yogurt sauce:
You can find a copy of this recipe online in a few places to give you an idea of ingredients used in the book. While it contains quite a few ingredients you might not keep on hand, the book uses them in most recipes so once you have the supplies for one you will likely have enough for most of the book. Overall I found the book easy to follow with good photography and background information. If you are looking for something new, even indian food-wise, give this book a checkout.