Take a large bowl and add the flour, sugar, cacao, espresso powder, baking powder and baking soda. Mix it together and while mixing add the milk.
Whisk it through and than add the eggs one by one. After each egg is added whisk through to make sure they are incorporated.
Finish by adding the sunflower oil and the vanilla and mix to a smooth batter. Add the pieces of chocolate with a spoon.
Cover your baking tin with baking paper and brush the sides with oil. Divide the batter into two equal parts. If you have two tins you can bake them at the same time. If not you can bake one after the other. It just takes a little longer.
Place half of the batter in each tin, smooth the surface and bake in the oven for about 40 minutes or until cooked through. Test this by inserting a wooden skewer.
Take out of the oven and leave to cool upside down. That way the top with flatten making it easier to fill later. Leave to cool to roomtemperature
While the cakes are cooling down, make the buttercream. Melt the white chocolate au bain marie. Leave this to cool to roomtemperature.
Add the soft butter, icing sugar and vanilla into the bowl of your food processor and whisk to a light and fluffy buttercream. Leave to whisk for about 10 minutes.
Add the cooled down chocolate and whisk it through. You're now ready to assemble the chocolate cake.
Place the first half on the counter with the flat side on top. Spread a generous layer of the buttercream on. Divide strawberries over the cream and add a small layer of cream on top of the strawberries. Place the second cake on top.
Cover the top of the cake with more buttercream and finish with some strawberries. Add some mint leaves to finish it off and keep in the fridge until eating.