Preheat the Oven: Preheat the oven to 375°F. Line two baking sheets with parchment paper so the flatbreads bake evenly and cleanup stays painless.
Prep the Flatbreads: Place the premade flatbreads on the prepared baking sheets. Brush the melted butter around the edges, then sprinkle the sesame seeds over the buttered crusts.
2 premade stone-fired flatbreads, ¼ cup unsalted butter, 3 tablespoons sesame seeds
Par-Bake the Crusts: Bake the flatbreads for 10 minutes. This helps the edges get golden and sturdy enough to hold the beef, cheese, and toppings.
Brown the Beef: While the flatbreads bake, heat a large skillet over medium-high heat. Add the ground beef, season it with salt and black pepper, and cook until browned, breaking it apart with a wooden spoon as it cooks.
1 pound ground beef, Salt, Black pepper
Add the American Cheese: Drain any excess grease from the skillet, then return the beef to the pan. Add the American cheese slices and stir until melted into the beef.
6 slices American cheese
Build the Flatbread Pizzas: Drizzle ketchup over the center of each par-baked flatbread, then add a drizzle of mustard. Sprinkle the shredded mozzarella over the sauce, then top with the cheesy ground beef and sliced tomatoes.
Ketchup, Mustard, 1 pound whole milk mozzarella, 2 Roma tomatoes
Bake Until Golden: Bake the flatbread pizzas for 12 to 15 minutes, or until the mozzarella is melted and bubbly and the crusts are deeply golden around the edges.
Finish and Serve: Drizzle the flatbread pizzas with garlic aioli, then top with thinly sliced pickles and baby arugula. Slice into 16 pieces and serve warm.
2 pickles, Garlic aioli, Baby arugula