Ingredients
1/3 cup Dijon mustard
1/3 cup mayonnaise
Kosher salt and freshly ground pepper
12 small slices rustic bread, lightly toasted
Thinly sliced Beaufort, raclette, Gruyère, or other Alpine melting cheese
Preparation
In a small bowl, whisk together mustard, mayonnaise, and 2 tablespoons water until smooth; season with salt and pepper. (The sauce can be made up to 5 days ahead and refrigerated in an airtight container.)
Evenly slather lightly toasted bread slices with a layer of mustard sauce. Top evenly with cheese and place on a baking sheet; broil until cheese is melted and bubbly, 1 to 2 minutes, and serve immediately.
