• 1 ¾ cups all-purpose flour (220g)• ¼ cup granulated sugar (50g)• ¼ cup light brown sugar firmly packed (50g)• 2 teaspoons cornstarch• 1 teaspoon baking powder• ¼ teaspoon baking soda• ½ teaspoon salt• ¼ cup very hot water boiling or steaming• ¼ cup natural cocoa powder (25g)• 4 Tablespoons unsalted butter melted• 1 large egg room temperature preferred• 1 ½ teaspoons vanilla extract• ¾ cup buttermilk (177ml)• ⅓ cup mini chocolate chips
Whisk in butter until combined (it's OK if small lumps form). Add egg and vanilla extract to cocoa mixture and whisk well. Addbuttermilk and whisk until smooth.
Lightly but thoroughly grease and flour (or spray with baking spray) a 12 count donut tin. Then, drop batter evenly into prepared donut molds using a piping bag.
Transfer to center rack of 350F (175C) oven and bake for 10-12 minutes or until a toothpick inserted in the thickest part of a donut comes out clean or with fudgy crumbs.
Combine chocolate chips and coconut oil in a small microwave-safe bowl and heat in 25-second intervals, stirring well in between, until chocolate and oil are completely melted.
Dip the smooth surface of each donut entirely into the chocolate glaze. Return to a cooling rack for the glaze to set before enjoying. Decorate glaze with sprinkles.