This versatile recipe can be made into smaller patties as an appetizer, using the mustard-yogurt sauce on the side as a dip. It can also be served on a plate with a green salad, or in a whole-wheat pita. Do not boil sweet potato as that will add excess moisture to patties.
Heat small fry pan over medium heat. Add mustard seed, cumin and coriander seed. Stir constantly until fragrant and just starting to brown, about 2 minutes. Remove from heat. Gently press seed with back of a wooden spoon to crush slightly.
Combine chickpeas, sweet potato, egg, walnuts, bread crumbs, onion, cilantro, cayenne pepper and crushed seed in processor. Pulse until almost smooth, but with pieces of chickpeas and walnuts still visible.
Use a 1/4 cup measuring cup to scoop out mixture. Form into patties and place on lightly floured baking sheet. Place in refrigerator for one hour to firm up.
Heat large, non-stick fry pan over medium heat. Add canola oil. Place patties in pan. Cook about 4 minutes per side, until browned. Place on paper towel to absorb excess oil. Serve with a dollop of mustard yogurt sauce.
Combine yogurt, fresh cilantro, mustard and garlic in bowl. Refrigerate.
Serving Size 1 patty plus 1 Tbsp sauce
* Percent Daily Values are based on a 2,000 calorie diet. Your daily value may be higher or lower depending on your calorie needs.