Crust: combine water, yeast, sugar, salt and oil. Add flour until a soft dough forms and pulls away from the sides of the bowl (do by hand or electric stand mixer). You may need less or more flour. The goal is soft, smooth dough so judge by feel not by exact flour amounts. Knead 2-3 minutes. Cover dough lightly and let it rest until doubles in size, about an hour

Preheat the oven to 425 F and position an oven rack in the lower third of the oven.

Streusel topping: stir together brown sugar, flour and cinnamon. Add soft butter and mix with pastry blender or fingers until mixture is crumbly and butter is well-distributed.

Apples: heat the butter in a skillet until melted. Add the chopped apples, brown sugar and cinnamon, and cook, stirring often, until the apples are tender (but not mushy) and the mixture is thick and bubbly, 4-5 minutes.

Press the dough into 2 9 pizza pans. The dough should be about 1/4-inch thick. Scoop spoonfuls of the apple mixture over the dough. It wont cover the dough completely, just distribute the apples as evenly as possible. Sprinkle the cinnamon streusel over the top of the apples. Let the pizza rest for about 10 minutes to allow the dough to puff slightly.

Bake 12-15 minutes, until edges are browned and topping is hot and bubbly. While it, prep the glaze.

Glaze: Heat butter and milk in a medium saucepan until melted. Remove from heat. Add vanilla. Mix in the powdered sugar gradually, whisking until the glaze is smooth.

Rest for 15 minutes before drizzling the glaze over the top. Serve warm. Perhaps with vanilla ice cream or whipped cream.