In a large saucepan over medium low heat, melt butter. Add apple slices and cinnamon and stir until softened. Set aside
Roll out your pizza dough and set on a parchment lined pizza pan or baking stone. Cook for about 5-7 minutes and then remove from the oven. Top with apples.
In a small bowl, add all the topping ingredients and using a pastry cutter or two forks, cut the butter into the rest of the ingredients until crumbly. Sprinkle the crumbles all over the top of the pizza.
Bake for 20-25 minutes or until the crust is lightly golden and the crumbles are set and golden as well. Remove from oven and allow to cool for 10 minutes or so.
As your pizza is cooling, combine all the glaze ingredients in a small bowl and stir. Add more or less milk according to the thickness you prefer. Then, go ahead and glaze that pizza!
Slice and enjoy!