Preheat oven to its hottest temperature (typically around 500 to 550 degrees F).
Flour a clean work surface and stretch the dough into a roughly 10-inch circle. Start by flattening it into a disc and gently pressing around the edges to form a small edge, then use two hands underneath the dough to stretch it from the center outwards. You can use two fists to gently coax it into shape, with your hands at a slight angle to let gravity help you.
Once the oven is preheated and your dough is ready, open the oven slightly to let some heat escape and switch on the broiler to HIGH. Close the oven door. Then, preheat a cast iron pan on the stove over medium-high heat for about 5 to 10 minutes.*
Carefully lay the stretched dough flat on the cast iron pan. Then transfer the cast iron to the oven and cook under the broiler for about 2 to 5 minutes, or until the crust is golden brown.otate the pan halfway through cooking to ensure it cooks evenly.
Transfer the cooked pizza dough to a cooling rack or cutting board. Dollop mascarpone onto the crust and let it melt slightly before gently spreading it into an even layer, leaving about a half-inch border around the edge of the pizza. Next, top with slices of strawberry and banana.
Finish the pizza with a criss-cross drizzle of Nutella. To easily drizzle Nutella over something, make a piping bag with a sandwich-sized plastic bag by cutting off one corner. Place the Nutella in the bag, then gently squeeze it over the pizza.
Slice into 6 triangles and serve immediately, or let cool and store in an air-tight container in the refrigerator. This pizza can be served cold later on and will keep for up to 2 days in the fridge.