Sift the flour, add the baking soda and cocoa and mix. Pour the milk into a bowl and add the lemon juice, then leave it to stand for a bit. Beat the butter with half the sugar.
Gradually, one by one, add the eggs and then the remaining sugar. Begin adding the milk mixture and 2 tablespoons of flour at a time. Divide the resulting dough into 2 parts and pour it into two cake molds, pre-coated with margarine and covered with baking paper.
Once baked, leave them to cool. Melt the chocolate for the glaze in a water bath, add the sugar and cream.
Cut each layer into two parts, stick them together with the chocolate glaze. Smear the top of the entire cake with a part of the glaze.