Preheat the oven to 180°C and grease and line a 30cm x 20cm lamington tin with cooking spray and baking paper.

In a large bowl, cream together the dairy-free butter and caster sugar with an electric mixer until the mixture is light and fluffy and starting to get pale in colour. Add in the vanilla and continue to beat. Gradually add the eggs one at a time, beating the mixture completely after each addition.

In a separate bowl, sift together the flour, baking powder and salt and mix to combine. Slowly add the flour mixture a little at a time, to the wet ingredients, alternating with the dairy-free milk mixing until just combined. You might want to do this step by hand with a spatula to ensure the mixture does not get overmixed.

Pour the batter into the lined cake pan and bake for 30-35 minutes or until the cake is cooked through and springs back when lightly touched. Let the cake cool in the pan for 10-15 minutes before turning out onto a wire rack to cool completely.

Once the cake is cool, cut it into squares or rectangles depending on the size you want your lamingtons to be.

Make the icing by sifting together the icing sugar and cocoa powder in a large bowl. Add the boiling water, dairy-free butter and vanilla and stir until smooth and shiny. You want the icing to be quite thin to be able to coat the cake, so adjust the water as needed to maintain the correct consistency.

Spread some desiccated coconut on a large plate. Using two forks, dip each square piece of cake into the chocolate icing to coat completely. Allow any excess icing to drip off before rolling it on the coconut. Use a small amount of coconut on the plate at a time and replace as needed throughout the process as it can get clumpy with drips of chocolate.

Set the lamington aside on a plate to set and continue this process until all of the cake has been coated.