3/4 cup dry lentils 1 1/2 cup water 2 tablespoons cider vinegar 1 tablespoon peanut oil or olive oil 1 cup onion, finely minced 4 large cloves garlic, minced 10 large mushrooms, minced 1/2 cup walnuts, very finely minced 1 teaspoon salt **Optional** 1/2 pound fresh spinach, finely minced 1 teaspoon dry mustard fresh black pepper, to taste 1/2 cup fine dry breadcrumbs or wheat germ
Place lentils and water in a small saucepan and bring to a boil. Lower the heat and simmer, partially covered, for about 30 minutes, or until the lentils are soft and the liquid is gone. Transfer to a medium-sized bowl, add vinegar, and mash well. Heat oil in a medium-sized skillet. Add onions and saute over medium heat for about 5 minutes. Add all remaining ingredients except breadcrumbs or wheat germ, and saute 5 to 10 minutes, or until all the vegetables are tender. Add the saute and crumbs to the lentils and mix well. Chill for about an hour before forming patties. Form 4-inch-diameter burgers. Fry in a small amount of hot oil on both sides until heated through and crispy on the outside, or broil for 5 to 8 minutes on each side.
NOTES : You can saute the vegetables while the lentils cook. The burgers can be made up to several days in advance and stored in the refrigerator until just before cooking. Uncooked burgers can be individually wrapped and frozen. Defrost before cooking.