1. Prepare eggplant: Preheat oven to 450°F. In a small bowl, combine olive oil and vinegar and season with salt and pepper. Lay eggplant rounds on a baking sheet and, using a brush, coat each piece with the olive oil mixture, flip the eggplant, and brush the remaining sides. Bake the eggplant for 20-25 minutes, turning once. Remove and let cool. (Note: eggplant can be prepared up to one day in advance.)



2. To make each sandwich, spread 1 tablespoon of hummus on a slice of bread. Divide the eggplant by four, and top each hummus-coated bread slice with eggplant. Cover eggplant with 1/4 cup of mint, and place three slices of feta cheese on top.



3. Place the ingredient-covered slice and a second slice of bread in a toaster oven on high until the bread is lightly browned and the cheese has softened.



4. Place a lettuce leaf over the feta, and spread one tablespoon of hummus on the remaining slice of toast. Place hummus-side down onto lettuce to close the sandwich, cut in half, and serve.

Makes 4 sandwiches.