Preheat the oven to 425°F. Lightly grease two standard doughnut pans.
2. Beat
In a medium-sized mixing bowl, beat together the butter, vegetable oil, banana, and sugars until smooth.
3. Eggs
Add the eggs, beating to combine.
4. Stir
Stir in the baking powder, baking soda, nutmeg, cinnamon, salt, and vanilla.
5. Alternate
Stir the flour into the butter mixture alternately with the milk, beginning and ending with the flour and making sure everything is thoroughly combined.
6. Pipe
Pipe the batter (using a pastry bag) into the lightly greased doughnut pans, filling the wells to about 1/4" shy of the rim.
7. Bake
Bake the doughnuts for 10 minutes.
8. Cool
Remove them from the oven, and wait 5 to 7 minutes before turning them out of the pans onto a rack. Enjoy warm; or cool completely, and store airtight.
1. Combine
Combine powdered sugar, cocoa powder and RumChata in a medium-size bowl. Stir well until all powdered sugar is incorporated.
2. Dip
Dip doughnut tops into glaze and place on a wire cooling rack until glaze is set.
3. Sprinkle (optional)
Sprinkle the tops of the glazed doughnuts with the coconut flakes before the glaze sets on the cooling rack.