Wash potatoes, cut in half, and place in saucepan of cold water. Cook, covered, over medium heat for 25 to 30 minutes or until tender.
Drain and dice potatoes when cool.
Add vegetables and egg to potatoes, and toss.
Coarsely mash garbanzo beans with a fork or masher.
Add remaining ingredients, except oil and buns, and mix thoroughly. Form into four patties.
Meanwhile, heat oil in large skillet and cook over medium heat until brown. Flip over and brown other side.
In a medium saucepan, bring 1½ cups of water to a boil. Add the lentils, reduce the heat, and cook until beans are softened, about 15 minutes. Drain and set aside.
Preheat oven to 375 degrees.
Scrub sweet potatoes (or peel if you prefer) and cut into wedges.
Place sweet potatoes in a bowl and add olive oil, salt, and pepper.
Toss until wedges are well coated.
Preheat oven to 400 degrees.
Grease muffin tin or insert paper muffin cups.
Soak oats in the yogurt, set aside.
Using an electric mixer, beat the egg, oil, applesauce, and brown sugar.