Preheat the oven to 375ºF. Spray two mini muffin pans with cooking spray. Set aside.

In a large bowl, whisk together butter, applesauce, sweet potato, maple syrup, browin sugar, baking soda, and eggs. Stir in milk and whisk again. Add cocoa powder and flour and stir with a wooden spoon or spatula until just combined. Do not over mix. The batter should be thick, but if it appears too thick you can add a bit more milk. Finally, stir in the chocolate chips.

Divide the batter evenly amongst the muffin tins (should be about 40 mini muffins) and sprinkle with a few more mini chips if desired. Bake about 10 minutes, watching carefully as you don't want to over bake them. The tops should spring back when touched and a toothpick inserted in the center should come out clean. Let cool for a few minutes in the pan before removing from the tins and letting cool completely on a rack.

To make the glaze, whisk together powdered sugar, vanilla, and milk in a large bowl until smooth. Dip the tops of cooled muffins in the glaze, allowing extra to drip back into the bowl. Place glazed muffins back on the cooling rack to allow the glaze to set.

Glazed muffins are best eaten the day they are made, but will keep in an airtight container for several days.