Preheat the oven to 175°C. Line a 12 hole cupcake tray with paper cupcake cases.

In a stand mixer, cream together the olive oil and caster sugar until mixed. Add the almond milk and apple sauce and mix until everything is thoroughly combined.

Mix all the dry ingredients together in a bowl and add to the wet ingredients in 3 batches, mixing between each addition. Stop mixing as soon as everything is combined to ensure you don't overmix the mixture.

Divide the batter equally between the 12 cupcake cases and bake for 20 minutes, or until a skewer inserted into the cupcakes comes out clean. Allow to cool in the tray for 10 minutes and then transfer to a cooling rack to cool completely.

To make the frosting, beat the butter in a stand mixture on a high speed for 5 minutes until light and fluffy.

Meanwhile, sift the powdered sugar and cocoa powder together. After 5 minutes, add the icing sugar and cocoa powder mixture gradually to the butter, mixing between each addition. When it's all combined, add the almond milk and beat again for another 5 minutes until completely smooth. You may need to add a little more almond milk if your frosting is too thick.

Pipe the frosting onto the cupcakes, or just spread it on, whatever you prefer. If you like, drizzle some dark chocolate over the top and sprinkle on some chopped hazelnuts.