Heat the oven to 180C/350F/gas mark 4. Grease two clean, empty 400g food tins and line the bases and sides with greaseproof paper, make sure that the paper comes a little above the top of the tin for easy removal.

Whisk together the oil, buttermilk, egg yolk, vanilla extract, sugar and salt.

Mix the flour, cocoa powder, baking powder and bicarb of soda together and sift into the wet ingredients, whisk to combine then stir in the coffee.

Divide the mixture evenly between the tins (I use a digital scale for accuracy).

Bake in the centre of the oven for 20-30 minutes until a skewer inserted into the centre comes out with a few moist crumbs but no wet batter. Leave to cool in the tins. I like to refrigerate the cakes overnight, still in their tins, so that they are easier to slice.

To make the buttercream, whisk the butter until light and fluffy, sift in the icing sugar and add the jam, continue to whisk until very light and smooth.

Whisk in the vanilla extract and a little food colouring, if desired (the jam will colour it pink, the colouring will just make the pink a little stronger).

If the buttercream is too stiff, whisk in a little bit of milk, a teaspoon at a time, until it reaches the desired consistency.

Fit a piping bag with a Wilton 2D nozzle (to make roses), spoon the buttercream into the bag and twist the top closed. (Or just spread the buttercream onto the cakes with a palette knife).

Remove the cakes from the tins and trim the domed tops. Slice each cake into three even layers.

Pipe a swirl of buttercream onto each cake layer then stack them, try to stack them in the same order as they were sliced so that the cakes are even.

Will keep for a few days in an airtight container.