Preheat your oven to 450 degrees. Roll out your pizza dough.
Whisk together the mustard and olive oil. Brush the blend over the pizza dough, leaving about a 1" ring for the crust.
Heat the remaining tablespoon of olive oil in a medium skillet. Add the fennel and sauté for 2-3 minutes. You don't want to completely soften the fennel as it will cook as it bakes on the pizza.
Distribute the apple slices and fennel around the pizza, layering them as needed. Crumble the gorgonzola on top, and bake in the oven for 12-15minutes, or until the crust is done and the cheese is slightly golden.
Remove from oven, sprinkle with cracked pepper, and serve.