3/4 pound yams (or sweet potatoes), sliced
3 large whole scallions, very thinly sliced
1 teaspoon dry mustard
Grated zest of 1/2 lime, plus juice
Salt and freshly ground black pepper, to taste
1/4 to 1/2 cup cornmeal, preferably stone-ground
1/4 cup reduced-fat mayonnaise
2 tablespoons Dijon mustard
2 teaspoons dried or chopped fresh rosemary
2 teaspoons fresh lime juice
1. Steam yams until very soft, about 20 minutes on the stovetop or 2 to 4 minutes in a microwave oven. (If using a microwave oven, drape a damp paper towel over the top of the yams.)
2. Cool yams until easily handled by hand. Using your fingers, peel skin from the slices. In a medium bowl, coarsely mash yams with a fork.
3. Mix in salmon, scallions, mustard, the zest and juice of 1/2 lime, plus salt and pepper to taste. Blend until well combined.
4. Shape mixture into 8 cakes, using about one-third cup for each. Arrange fishcakes on a plate, cover and refrigerate 1 to 4 hours.
5. Spread cornmeal over a small plate. Coat a large non-stick skillet generously with cooking spray and heat until hot on medium-high heat. Meanwhile, dredge fishcakes in cornmeal, coating them all over. Cook until golden brown, 3 to 5 minutes on each side.
6. Make the sauce by mixing together the mayonnaise, mustard, rosemary and lime juice in a small bowl.
7. Serve the sauce with the salmon cakes. If desired, serve fishcakes in hamburger buns, preferably whole wheat, along with a lettuce leaf and a dollop of the sauce.