Preheat the oven to 180°C and line a muffin tin with 12 patty cases / cupcake liners and a second tray with 2.
In a small bowl, mix together the white vinegar and almond milk. It will split and curdle but this is ok! Set aside.
In a medium bowl, whisk together the plain flour, cocoa powder, hazelnut meal, baking powder and bicarbonate of soda.
In a large mixing bowl, whisk together the canola oil, white sugar and vanilla until combined.
Add the dry ingredients to the oil and sugar mixture, alternating with the milk until the batter just comes together, scraping down the sides of the bowl as necessary.
Spoon mixture into patty cases ensuring they are only ¾ full before placing them in the oven for 20 minutes or until they spring back when lightly touched. Remove from the pan and set aside on a wire rack to cool completely.
Prepare the buttercream frosting. In the bowl of an electric mixer, beat together the dairy free butter and vanilla until creamy. Add in the hazelnut spread and continue to beat together.
Add in 1 cup of icing sugar and mix until fully incorporated. Add in the second cup and beat until creamy, adding 1 tablespoon of almond milk. Repeat this with the remaining icing sugar and milk, using just enough to ensure the frosting is smooth and creamy. Add a pinch of salt and beat to combine.
Cut out small holes in the top of your cupcakes and fill with a spoonful of vegan hazelnut spread.
Place the buttercream in a piping bag fitted with your favourite piping tip and pipe swirls around the top of each cupcake before finishing with a sprinkle of crushed hazelnuts.