Preheat oven to 180°C (fan-forced). Grease and line three 19 cm cake tins (or two for thicker layers).

In a large bowl, whisk together flour, cocoa powder, bicarbonate of soda and salt.

In another bowl, whisk oil and sugar until combined. Add eggs and vanilla and whisk until smooth.

Add buttermilk, vinegar and red food colouring to the wet mixture and mix until evenly coloured.

Add the dry ingredients to the wet ingredients and mix until just combined. Do not overmix.

Divide evenly between tins.

Bake for 35–40 minutes (40–45 if using two tins), or until a skewer inserted into the centre comes out clean.

Cool in tins for 10 minutes, then transfer to a wire rack to cool completely.

Beat butter until pale and fluffy. Add cream cheese and beat until smooth. Gradually add icing sugar, then vanilla and salt. Beat until creamy but do not overwhip.

Once cakes are completely cool, use a long serrated knife to gently level the tops if needed.

Place first layer on serving plate and spread with frosting. Repeat with remaining layers.

Apply a thin crumb coat and chill for 30 minutes.

Apply final coat of frosting and smooth sides. Chill until firm.

Just before serving, dust lightly with raspberry powder.