In a small bowl mix together the dry ingredients, flour, (I like to use bread flour but all purpose will work to) cinnamon, salt, baking powder, and baking soda.
In a pan on the stove start to brown the butter. Once it starts to smell amazing and look foamy and brown then you know it’s done. Put it aside and let cool while you mix the wet ingredients.
Mix together the wet ingredients and sugar in a large bowl. Mix the sourdough, brown sugar, apple cider, yogurt, egg and vanilla.
Mix the dry ingredients into the wet. Combine well and add in the browned butter.
Dice up your apples, leaving ½ cup of apple to the side. Fold in the diced apples.
Make the crumble topping. Mix together the brown sugar, white sugar, flour and cinnamon. Mix well. Add in the grated butter and mix well. Then add in the remaining 1/2 cup of Apples. Set crumble aside for now.
Prepare two 9x5 loaf pans lined with parchment paper. Divide your batter evenly into each of these pans.
Divide your crumble topping in half and cover each loaf with it.
Bake at 350 degrees for 50 minutes or until a toothpick comes out clean.
If you want, this is the time to make the apple frosting glaze. Mix together the apple cider, cream, and powdered sugar. You might need to add more cream or apple cider depending on the thickness you desire for the glaze. Drizzle on the bread before the bread has completely cooled.
Allow to cool for at least 20 minutes before cutting into it - this is a hard part but very necessary. After 20 minutes slice, serve, and enjoy!