Pre-heat your oven to 160C Fan/180C/350F/Gas Mark 4 and grease two 6 hole donut tins with the butter
Mix together the caster sugar, milk, vegetable oil, Nutella and eggs in a bowl with a whisk
Add the self raising flour and cocoa powder, and whisk in
Stir in the chopped roasted hazelnuts if using
Divide the batter between the trays. You can put the batter into a piping bag to make it a bit neater to dispense into the trays, but you can do it with a spoon too
Bake them for 12 minutes, then remove them from the tin (I use a spoon to gently prise them out) and leave to cool on a cooling rack
Set the donuts onto a rack with a baking tray or some baking paper underneath to catch any drips
Warm the Nutella for 30 seconds in the microwave, stir then warm for longer if needed
Dip the top half of the donuts in the melted Nutella and place back on the rack
Sprinkle on the chopped roasted hazelnuts if using, then leave to set - or dig straight in!
Store leftover in an airtight container and eat within 3 days
Video
Notes
Make sure your ingredients, particularly the eggs, are at room temperature before you start baking.
You can use a different type of oil besides vegetable oil. I'd recommend one that doesn't have a strong flavour, canola and sunflower oil would both work well.
I used ready prepared chopped and roasted hazelnuts for this recipe. You can roasted and chop your own too. To roast, place onto a baking tray and put in the oven for 15 minutes at 180C. Every 5 minutes, stir them around on the tray. If they have skins on, take them out of the oven and let them cool, then wrap them in a tea towel and shake them around and the skins will come off. You can then chop them up.
You can use any other brand of chocolate hazelnut spread, it doesn't have to be Nutella. Just be aware if you use a lower sugar brand, the topping won't be as sweet.
For the milk, you can use plant milk or cow's milk. Both will work so you can easily make them dairy free by using plant milk.
You will need a 12 hole donut pan (or two 6 hole donut pans) to make this recipe. Check the recommend equipment section for a link to the one I use.
Although I provide cup measurements, I highly recommend weighing your ingredients out using digital kitchen scales. It is the most accurate way to measure ingredients and will ensure the best results. Digital scales are very low cost and can be purchased for around £12 ($16.50) .
For teaspoon (tsp) and tablespoon (tbsp) measurements, please use measuring spoons and not the type of spoons you eat with. Again this will ensure accuracy and provide the best results.