1. Line a 5x4-inch disposable aluminum loaf pan with plastic wrap, using enough so that excess hangs over the sides.
2. Sprinkle the gelatin over the water in a small cup and let sit until the gelatin softens, about 5 minutes.
3. Meanwhile, pulse together the shredded cheese, dry milk powder, salt and cream of tartar in a food processor until combined, about 3 pulses.
4. Bring the milk to a boil in a small saucepan. Remove from heat and immediately whisk in the softened gelatin until it is completely dissolved and the mixture is smooth.
5. Turn the food processor on so it is running, then slowly add the hot milk mixture to the cheese mixture until smooth, about 1 minute, scraping down the bowl as needed.
6. Immediately transfer the cheese to the prepared pan. Working quickly, pack the cheese firmly into the loaf pan to eliminate most air pockets, then smooth the top. Fold the overhanging plastic tightly against the surface of the cheese and refrigerate for at least 3 hours. The cheese can be stored in the refrigerator, wrapped tightly in plastic wrap, for up to 1 month.
Note: Be sure to use whole dry milk powder, not nonfat dry milk powder, as it will make a difference. I purchased my whole dry milk powder from King Arthur Flour.Nutritional values are based on the whole recipe