Butter the bread on one side. Place the four slices butter side down in a frying pan. Evenly spread the Dijon mustard.
Then add the cheese, tomatoes and microgreens to each piece of bread. Top with the other buttered slices (butter side out) and cook over medium heat.
Watch and flip once. When your bread is lightly browned, season with salt and pepper to taste and enjoy!
Other cheeses can replace the fresh Mozzarella such as Provolone, Fontina or regular Mozzarella. Instead of basil leaves you can use basil pesto. Any thick cut sturdy bread can work for this: sour dough, rye, ciabatta etc.