- 6 Tbs (90 ml) mayonnaise
- 1 Tbs (15 ml) Dijon-style mustard
- Salt and freshly ground pepper to taste
- 1 medium onion, peeled, cut into quarters, and sliced very thinly
- 8 thin slices white or whole wheat bread, crusts removed.
- 4 Tbs (60 ml) freshly grated Parmesan cheese
Mix together the mayonnaise, mustard, salt, and pepper in a small bowl. Combine 5 tablespoons of the mayonnaise mixture with the sliced onion. Spread the onion mixture on 4 slices of bread and top with the remaining bread. Spread the remaining mayonnaise mixture on the tops of the sandwiches and sprinkle with the Parmesan cheese. Cut each sandwich into quarters and place on a baking sheet. Bake in a preheated 350F (180C) oven until light golden brown, about 15 minutes. Serve immediately. Serves 4 to 6 as an appetizer.