Roll out the pizza dough onto a large pizza pan. Bake until just beginning to brown on around the edges (slightly under than normal) about 15 minutes. Remove from oven and allow to cool down.
In a large bowl, whisk together the ricotta, mascarpone, sugar, vanilla and salt until smooth. Spread this mixture onto the cooled pizza crust. Drizzle the top with nutella and then top with marshmallows. Return to oven under the broiler and cook until the marshmallows are toasted. You can also use a kitchen torch for this. Remove from oven and sprinkle with graham cracker crumbs. Cut and serve!