Grease three 15cm round tins and line the base with baking paper.
Preheat oven to 160ºC
Mix lemon juice and milk, allow to curdle.
With a stand mixture, whisk eggs until light and fluffy.
Mix chocolate with the coffee and mix well. Set aside.
Sieve the flour, baking powder, bicarb, sugar, salt and cocoa powder.
Turn the mixer down to the lowest setting, add oil and whisk well.
Add the milk, the coffee mixture and then add the dry ingredients slowly until completely combined.
Divide between the tins.
Bake for 30 to 35 Minutes until a tester comes out clean.
Allow to cool completely in the tins.
Combine the butter and the icing sugar in a stand mixture.
Using the paddle attachment, beat well.
Add the milk and caramel and combine well.
Remove cake from tin and remove baking paper. Place onto serving dish.
Spread a third of the buttercream on the first cake. Drizzle caramel on top of the buttercream.
Repeat with the next two cake layers.
Store in an airtight container for up to a week.