Made a hood to wear at home because my head was cold. The hood is just a big square folded in half and sewn part way into the middle in a Y shape to make sort of a pair of little darts, and then the other two edges sewn together and the remaining hole in the back gathered in somewhat uneven cartridge pleats, with the extra fullness being pleated into the neck.
The cape part is the rest of the fabric (which was a 1.3 m piece of cotton flannel from the thrift store) with the larger leftover rectangle forming the back and the smaller rectangle being cut in half mostly diagonally and added to the front.
It was a very quick project done almost entirely on machine, which is unusual for me. There are a few things I'd do differently next time - I'd make the hood a bit shorter so the front edge doesn't block my view so much, and I'd put the button loop right on top of the neck seam instead of sandwiching it inside the front edge seam of the hood. I'd have to cover the ends of the loop with a patch, which would be a good use for the neck hole cutout.
I think this pattern would work on a wide variety of sizes of fabric cut, as long as you cut the hood out first. Then the remaining piece could be cut into the cape portion and it might be very small or very large, and the two angled front pieces could be made to fit the edges on either side of the neck hole by adjusting the angle at which you cut that second rectangle apart.