Slice them into 2-cm thick slices, add to a food processor with tofu (without draining), low fat milk (or better yet, soy millk ), and maple syrup, then pulse until smooth.

It's good as is, but it will become even smoother if passed through a strainer. Form the leftovers (the size of a large egg) into a ball, paint on a wash of egg white, and bake to make a baked sweet potato confection. Great for a bonus snack.

With the strained paste, add the egg yolk and condensed milk (optional, to taste), mix well, and set on low heat. It will burn easily, so stir continuously. Remove from heat once the egg has been heated thoroughly enough.

Transfer to a plastic container, and wrap in plastic wrap directly over the surface to prevent drying. Press out any air pockets.

Once it cools down, chill it in the refrigerator, then it's ready.