Preheat oven to 350. In a small mixing bowl, add your milk and microwave it till warm. Add your instant coffee granules and whisk together till incorporated.
In a large mixing bowl, beat together your butter and brown sugar. Add in your applesauce, vanilla, and milk and espresso mixture and mix together till smooth. Add your eggs and briefly blend them in.
To the same bowl, add your oat flour, all purpose flour, baking powder, baking soda, salt, cinnamon, ginger, cardamom and allspice and mix together till you have a consistent muffin batter.
Scoop your muffin batter into your muffin tin, filling each cavity about 2/3 way full. Bake for 16-18 minutes, or until the tops are springy to touch and a toothpick inserted comes out clean.
In a small bowl, whisk together your powdered sugar, cinnamon, ginger, cardamom, and allspice. Add in your milk and whisk until well combined.
Drizzle over your muffins and devour!
*I recommend storing these muffins in the fridge, in an airtight container and they will last about a week.