Preheat oven according to directions on pizza dough. Unroll pizza dough and allow to rest for five minutes.
Melt butter in microwave, about 30-45 seconds. Spread a thin layer of butter on pizza dough.
Combine brown sugar and flour in a bowl. Pour remaining melted butter over dry ingredients. Stir to combine. Reserve 2 tablespoons to sprinkle on top. Spread remaining streusal over top of buttered pizza dough.
Bake pizza 5-7 minutes to get the crust lightly browned. Remove from oven and top with peach fruit filling. (Spoon the peaches onto the pizza but try not to drain too much liquid on top of crust or it will be too wet.)
Sprinkle with remaining brown sugar mixture and walnuts.
Bake an additional 5-7 minutes. Remove from oven and allow to cool at least 15 minutes.
Prepare glaze by combining powdered sugar and milk. Drizzle over warm pizza.
Serve warm. Keep leftovers in airtight container for one day.