Preheat the oven to 325° and coat a standard loaf pan with a little butter and flour.
Brown the butter in a small pot on medium to low heat, remove from the heat, and allow to cool.
Make the batter by combining granulated sugar, brown sugar, applesauce, and grated apple.
Add in flour, cinnamon, baking powder, baking soda, and nutmeg, stir until combined.
Then add in egg & brown butter, stir until just combined and pour batter into your prepared pan.
In a small bowl, combine all streusel ingredients and sprinkle over the batter.
Bake for 60-75 minutes until a knife comes out clean when inserted into the center of the loaf.
Allow to cool slightly, transfer to a wire rack, slice and enjoy!