Preheat the oven to 375 F. Place the bread side by side. Spread 1 Tbsp. Of creme fraiche on each slice, and 3-4 slices of tomatoes on top of the creme fraiche; sprinkle the tomatoes with herbs. Place 2 slices of ham on top of the tomatoes and top with 2 slices of cheese. Bake in the oven until the cheese is melted and oozing. Serve with whole grain mustard.