Combine bread flour, sugar, and salt in the mixing bowl of stand mixer and whisk till combined, about 30 seconds. Add yeast and whisk for another 30 seconds. Change out wire whisk with dough hook.
Add egg, butter, and milk. Turn on mixer on speed 2. Mix for about 5 minutes. Scrape down sides of bowl and dough hook. Remove dough hook and cover with a plate for 15 minutes.
Reattach dough hook, and mix for another 10 minutes to form smooth pliable dough. Remove dough and shape into a ball. Lightly oil mixing bowl. Return dough to bowl, cover with plate and allow to rise for about 1½ hours or almost double in size.
Lightly oil a 9-inch spring form cake pan. Peel and slice peaches into ½-inch slices. Mix all topping ingredients in a medium sized bowl until mixture resembles coarse breadcrumbs.
When dough is ready, remove from mixing bowl and place on a lightly floured surface. Punch it down gently and roll it out to fit the pan. Ease it into position. Arrange peaches on top of dough. Sprinkle topping over peaches. Cover with lightly oiled plastic wrap and set in a warm place to rise slightly for about 20 minutes.
Meanwhile, preheat oven to 375°F (190°C). Bake kuchen for 30 minutes or until golden brown. Allow to cool in pan for 10 minutes. Serve warm or turn onto a wire rack to cool completely.
**Peaches may be substituted with 3 large apples or a pint of blueberries.