This year, I’m working on a sourdough version of the apple crumble pie I usually make ... Here is how to make sourdough apple pie with oat streusel topping. Step 1: Preheat oven.

Read more: Mistakes Everyone Makes With Oatmeal In case you need ... off with a hearty sprinkling of crumble topping rather than a top layer of pie crust. A crisp topping, on the other hand ...