Slowly melt the butter and chocolate au bain-marie on a very low flame.
In a seperate bowl, whisk the eggs and Tagatesse with a mixer until the mixture is light and frothy. Add the melted butter and chocolate mixture to the egg mixture and whisk to combine well. Lastly, add the flour and whisk until blended. Refrigerate the batter overnight.
Preheat the oven to 180°C/Gas Mark 4.
Grease 4 equal sized porcelain ramekins with butter and dust with a little flour. Pour the chocolate mixture into the ramekins about 4/5s full and top with a piece of chocolate.
Bake for 10 minutes in the oven. Let the cake cool, remove from the ramekin and serve with fresh strawberries.