Pre-heat your oven to 160C Fan/180C/350F/Gas Mark 4, and grease and line two 8" cake tins (that are at least 2" deep)
In a mixing bowl, or a large jug, whisk together the vegetable oil, dairy free milk, vanilla extract and cider vinegar
In another mixing bowl, stir together the caster sugar, self raising flour and baking powder
Make a well in the centre of the flour mixture, and pour in the oil and milk mixture, whisk them together gently with a hand whisk until smooth, be careful not to over mix
Divide the mixture between the tins, use scales for accuracy if you like
Bake them for 35-40 minutes or until they are risen and a skewer inserted in the centre comes out clean. Leave them to fully cool either in the tins or remove from the tin and place on cooling racks
Make the buttercream by first mixing the dairy free butter on it's own for a few minutes until creamy. Then add the icing sugar, dairy free milk and vanilla extract, and mix until smooth. You can do this by hand or for best results use an electric mixer. If the buttercream is too stift, you can add more dairy free milk
If the cakes have domed on top, you can level them off with a cake leveller or a serrated knife
Put one of the sponges on your plate or cake stand and pipe or spread some of the buttercream onto it. Then top with the jam, I just spooned it on
Add the second cake layer, then dust the top with icing sugar
Store leftovers in an airtight container in a cool place and eat within 3 days
Video
Notes
I use oat or almond milk for this cake, but you can use any vegan milk that you prefer.
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.
For the best flavour, make sure to use a good quality vanilla extract and not an essence. You can also use a vanilla bean paste. I like to use the brand Nielsen Massey.
You do need to add the vinegar to this recipe to get a good rise - it reacts with the baking powder to create air bubbles. Cider vinegar is the best vinegar to use, but white vinegar would be a suitable replacement. Balsamic or malt vinegar (the kind you put on your chips) will not work. And don't worry - you can't taste the vinegar!
I've found that the best dairy free butter for vegan buttercream is Flora Plant. Stork Baking Block is also very good. Using a block dairy free butter is much better for the buttercream. A margarine or spread style dairy free butter will make the buttercream too loose. I also like to add some vegan shortening to stabilise it even more, but this is optional.
I filled the cake with buttercream and jam, but you can do only jam, or swap the buttercream for a vegan whipped cream.
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.