Ingredients

4 tablespoons unsalted butter 

6 ripe but still firm Forelle or large Seckel pears, 2 chopped into 1/4-inch pieces, and 4 cut crosswise into 1/4-inch slices 

1 teaspoon sugar 

1 tablespoon balsamic vinegar 

24 very thin slices white sandwich bread, crusts removed 

1/4 cup plus 2 tablespoons coarse whole-grain mustard 

8 ounces thinly sliced ham, preferably Black Forrest 

8 ounces thinly sliced Gruyere cheese 

Preparation

In a medium skillet over medium heat, melt 1 tablespoon of butter. Add chopped pears and cook, stirring, until just tender, 1 to 2 minutes. Increase heat to medium-high. Sprinkle pears with sugar and continue cooking until golden brown and caramelized, 5 to 7 minutes more. Add vinegar and swirl pan until liquid is absorbed. Remove from heat and transfer pears to a plate; set aside.

Melt 1 tablespoon butter in the same skillet over medium heat. Add pear slices, in batches if necessary, and cook until lightly browned, about 3 to 4 minutes per side. Remove from heat and set aside.

Spread the remaining 2 tablespoons butter over one side of each slice of bread. Lay buttered-side down on work surface and spread opposite side generously with mustard. Slice bread in half diagonally. Top half of the diagonal slices with 1 slice of pear, 2 slices of ham, and 2 slices cheese; top with remaining diagonal slices.

Heat a clean medium skillet over medium heat; working in batches, cook 5 to 6 sandwiches at a time, turning once, until cheese is melted and sandwiches are golden brown, about 1 1/2 minutes per side. Cut each sandwich in half to make two dozen hors d’oeuvres, if desired. Garnish each sandwich with 1/2 to 1 teaspoon reserved chopped pear mixture; serve immediately.