An incredible crunchy and delicious treat.
Make Mini Cakes:
Preheat the oven to 375 degrees F.
Coat six 6-ounce ramekin dishes with butter, and dust lightly with flour.
Set the ramekins on a sturdy baking sheet.
In a microwave-safe bowl or over the stove using a mini double boiler, melt the chocolate with the butter; let cool.
In the bowl of a standing electric mixer fitted with the whisk, beat the eggs, yolks, sugar, cream and vanilla on high speed until pale and fluffy, about 4 minutes.
Using a rubber spatula, gently fold in the chocolate, then fold in the cake flour just until no streaks remain.
Spoon the batter into the prepared ramekins and bake for 15 minutes, until the cakes have risen, the tops are dry and the centers are slightly jiggly.
Let stand for 5 minutes, then loosen with knife and let cool on wire racks.
Prepare your frosting by melting butter in a saucepan, stir in the dark brown soft sugar and the salt.
Bring to the boil and boil for 2 minutes, stirring constantly.
Remove from heat and add the milk, stirring all the while.
Return to heat and bring to the boil again.
Remove from heat and allow to cool until lukewarm.
Stir in the icing sugar and beat until smooth and cool enough to spread.
Once cooled, use a knife to spread frosting over sides and top of cake.
Crush toffee bars easily by sealing them in a heavy-duty, zip-top plastic bag, and crush with a rolling pin.
Sprinkle with crushed toffee and serve.