Dice yam into slices less than 1 inch thick, no wider than 1 1/2 inches (the smaller you cut the quicker they cook).
Place in bowl and pour brown sugar and cinnamon over top. Toss to coat.
Get 4 sheets of tinfoil and a pan. Divide yams in four, and pour each quarter onto a sheet of tinfoil, scraping out any leftover juices from the bottom of the bowl and pouring over top the four bunches.
Pull the corners of the tinfoil up, scrunching the tinfoil packages into bundles so no yam shows through, and place each bundle onto the pan, then in the oven.
Bake for 25-35 minutes, taking yams from oven at 15-20 minutes, and retossing them with a spoon so all the yams get done.