Since leftover mashed potatoes are often the inspiration for making a Shepherd’s Pie, I thought that the ultimate version should feature filling ingredients that are readily available and easy to use — hence the use of veggie burgers. Simply thaw them long enough so that you can chop them and they work like a charm, adding great taste and texture, enhanced by the ground walnuts. If you prefer, chopped seitan or tempeh may be used instead of the veggie burgers, just be sure to sauté them first in a little olive oil. Use the extra-rich Mashed Potatoes and Company on page 000, or your favorite mashed potato recipe.