Preheat oven to 350 degrees. Spray two non-stick donut pans (6 donuts each) with cooking spray and set aside.

Prick two smallish sweet potatoes with a fork and place on a glass plate. Microwave for 15 - 20 minutes, turning once during cooking time. Remove from microwave and set aside to cool. When cool enough to handle, peel and mash. Then measure out 1 cup of mashed sweet potato. This can be made several days ahead and stored covered in the refrigerator.

Whisk together the flour, baking powder, salt, baking soda and seasonings. Set aside.

Using a hand or stand mixer, beat together the softened butter, brown sugar and sweet potato until fluffy.

Mix in the eggs, milk and vanilla.

Add the flour mixture and mix until completely combined.

Scoop 1/4 c. donut dough into each donut pan well. Spread around with a spatula or your finger until evenly distributed.

Bake donuts for 12 - 13 minutes. Allow to cool on wire cooling rack in pans for about 10 minutes, then remove to finish cooling.

Combine the milk, butter, brown sugar and pinch of salt in a small sauce pan. Bring mixture to a boil and cook for about 30 seconds. Remove from heat and stir in the butterscotch chips. Stir until completely melted.

Dip the cooled donuts completely (both sides) into the glaze. Place on a wire rack to dry. They'll still be a bit sticky when ready to eat. They are messy and delicious!