Preheat oven to 180 degrees Celsius (350 degrees Fahrenheit).
Place the coconut oil in a large bowl and melt over a saucepan of boiling water or in the microwave (skip this step if not using any other oil).
Once melted, add the milk to the same bowl along with the pumpkin purée, vinegar, maple syrup, vanilla, salt and ground almonds.
Sift in the flour, baking powder, bicarbonate of soda, mixed spice and ground ginger.
Mix well, adding a splash more milk if looking too dry .
Transfer the mixture into a square baking tin lined with baking paper (I used a 23cm/9inch square baking tin).
Bake in the oven for 20-25 minutes until risen and an inserted skewer comes out clean.
Leave to cool before applying the frosting.
For the frosting:
Drain the soaked cashews and add to a food processor or blender with the maple syrup and lemon juice.
Whizz until completely smooth, adding some plant-based milk or water to thin out if necessary.
Spread frosting over the top of the cake.
Slice into 16 squares.
Tastes best when fresh, but keeps covered in the fridge for up to a few days.
*The acidity of the vinegar reacts with the alkali bicarbonate of soda to make the bread fluffy. If you can’t get hold of vinegar, substitute it with 1 tablespoon of lemon juice.**You can alternatively use almond flour.***You can alternatively use this coconut cream-based cream cheese frosting.