Step 1

Preheat oven to 350°F (175°C). Spray a 24-count mini muffin tray with cooking oil spray; wipe over excess with paper towel and set aside.

Step 2

In a large bowl, whisk all of the dry ingredients together. Make a well in the centre and add the oil, egg, vanilla and milk. Whisk the batter until smooth and lump free.

Step 3

Spoon the batter (about 2 teaspoons) into each muffin hole, filling to to 3/4 full. Bake for 10-15 minutes, or until they are golden in colour and a toothpick inserted into the centre of a donut comes out clean. Allow them to cool for 5 minutes and transfer them onto a cooling rack.

Step 4

Brush each donut over with a light coating of melted butter; combine the sugar and cinnamon together in a shallow bowl; toss each donut hole into the cinnamon sugar mix until evenly coated.

Step 5

Fill a piping bag with the Nutella. Using a a narrow nozzle, fill each donut with the Nutella until they puff up and expand (not too much or the donuts will overflow).