If you looked at some recipes, you'd assume no Indian dish is complete without a laundry list of spices that you have to assemble first. That's what I like most about this weeknight-ready dish: it uses all of one dried spice, and it's cinnamon.
Paneer makhani, or butter paneer, is a staple in America's Indian restaurants for a reason: it's hard to beat chunks of fresh cheese in a creamy, buttery tomato sauce. It's also drop-dead simple to make at home. Once you buy some paneer, virtually all your active work goes into making a gravy that's a lot like pasta sauce. Add in some chopped spinach (frozen is fine in a pinch) and you have the makings of a one-dish meal with some rice or poofy flatbread on the side.
This recipe is based on a carnivorous version by Floyd Cardoz, one of the country's top Indian chefs. His tomato sauce—which goes just as well with chicken as paneer—is lighter and fresher than the restaurant standards, with more spice and less cream.
I've made a few changes along the way to streamline the recipe, but the general principle is the same: cook onions, ginger, and a little chili in butter just until the onions start to sweeten, then add in canned tomatoes and simmer the sauce down (Cardoz vouches for roasted tomatoes, and I'd agree). Once it's smooth and puréed, you can add as much or little cream as you'd like.
Okay, about the spices. If you can find them, dried fenugreek leaves make a wonderful addition to the sauce, adding a subtle bitter-herbal flavor to balance out all the sweet tomato and cream. But you can skip 'em if you have to; this recipe is plenty satisfying as-is.