This turns out to be a really interesting question. 

Halwa, as it is found in South Asia, is a a pudding-like mixture made in its most basic form from a combination of: 

• ghee

• sugar or jaggery

• some form of flour (or lentils, or noodles, or starchy vegetables)

Halwa is cooked over a stove top until thick and creamy, and eaten with a spoon.

Halwa is in the same class as, but very different from, Halvah or Halva or Helva or Helava!) which is Persian or Arabic in origin and simply means a sweet, semisolid fudge that can be made from practically anything but traditionally has sesame as a dominant flavour. In Greece and Turkey, halvah is usually made from semolina and honey.