Confused Baked Double Chocolate Doughnuts

Doughnuts:

• Non-stick cooking spray
• 3/4 cup flour
• 3 tbsp cocoa powder
• 1/2 tsp baking powder
• 1/2 tsp baking soda
• 1/4 tsp salt
• 4 tbsp unsalted butter
• 4 oz dark chocolate chopped
• 1/2 tsp instant espresso powder
• 1/2 cup brown sugar
• 1 large egg yolk
• 1/2 cup buttermilk
• 1 tsp vanilla extract

Glaze:

• 2 cups icing/powdered sugar
• 1/2 cup cocoa powder
• 1 tsp vanilla extract
• 3-5 tbsp milk or water
• 1 tsp corn syrup

Garnishes: toffee chips, marshmallows, sprinkles, crushed Oreos, sliced fruit, etc.