6 thick slices sourdough bread, toasted
Country-style Dijon mustard
6 slices smoked deli ham (about 4.5 ounces)
1 large tomato, cut into 6 slices
8 ounces Gruyère, grated (about 2 cups)
3 teaspoons fresh oregano
Kosher salt, freshly ground black pepper
Preheat broiler. Line a rimmed baking sheet with aluminum foil.
Spread each toast with mustard, then top each with 1 ham slice and 1 tomato slice. Top evenly with Gruyère and oregano and season with salt and pepper. Arrange toasts on prepared baking sheet and broil until cheese is toasted and bubbling, 3–4 minutes. Serve hot.