Preheat oven to 180°C. Grease and line the base and sides of a 20cm (base measurement) square cake pan with baking paper.
Combine the chocolate and 1 cup (250ml) water in a small saucepan over low heat. Cook, stirring, for 5 mins or until chocolate melts and mixture is smooth. Set aside to cool slightly.
Use an electric mixer to beat the butter and sugar in a bowl until pale and creamy. Add the eggs, 1 at a time, beating well after each addition. Combine flour, almond meal and cocoa powder in a bowl. Add the flour and chocolate mixtures to the butter mixture, in alternating batches, stirring until just combined. Spoon into the prepared pan and smooth the surface. Bake for 45-50 mins or until a skewer inserted into centre comes out clean. Set aside for 30 mins to cool.
Meanwhile, to make the ganache, combine the chocolate and cream in a heatproof bowl over a saucepan of simmering water (don’t let the bowl touch the water). Cook, stirring, until chocolate melts and mixture is smooth. Cover with plastic wrap and place in the fridge for 30 mins or until just firm. Beat until smooth and creamy.
While the cake is cooling, make the caramel sauce. Place the sugar in a medium saucepan over medium heat. Cook, stirring with a wooden spoon, for 5-7 mins or until sugar dissolves and caramelises. Remove from heat. Carefully and slowly pour in the cream. Add the salt. Cook over medium heat, stirring, for 5 mins or until sauce boils and thickens. Set aside to cool slightly.
Turn the cake onto a serving plate. Use the end of a wooden spoon to pierce the cake at 3cm intervals. Place the warm caramel sauce into a jug. Carefully pour the caramel into each hole. Spread the top with milk chocolate ganache. Cut into pieces. Serve with any remaining caramel sauce.