To make chocolate cases: melt 200g ( 7 oz) chocolate over a pan of warm water, do not overheat, when three quarters of it is melted, remove from heat and stir vigorously, this should distribute the heat and melt the remaining chocolate without it getting too hot and going grainy .
Take a small teaspoon of melted chocolate and paint the inside of your mini muffin paper or the insides of your silicone ice block forms. If coverage is a bit skimpy don't panic. these set in the fridge in minutes and a second coat is easier and works better than trying to get one very thick coat. Put them in the fridge to harden. Reserve enough of your chocolate to cover the bottom of your forms once they have been filled with the ganache filling.
Put butter and cream in a saucepan and bring to boil, stirring all the time.
Remove from heat and add chocolate and liqueur.
Stir well until smooth (heat of mixture will melt chocolate) leave to cool a little, then let cool.
Use as soft filling for chocolates and tartes.
This does thicken up over time, and good chocolate is never refrigerated, just kept in a cool dry place. If these are refrigerated the filling gets very firm over time.
By now your ganache filling mixture should be cool enough to put into the chocolate cases, using a piping bag or a teaspoon, fill them with the ganache, (but not quite to the very top of the chocolate case) Then put them back into the fridge for a while, and once set a little solid, put a top of melted chocolate on them to seal them closed and refrigerate until the top too is solid. I like to keep these in the fridge for a least a few hours or somewhere nice and cool overnight before I try and get them out of the forms.
If using mini muffin papers, peel away the papers from the chocolates (this can be fiddly, don't press too hard as you peel them or your chocolate will break), If using the silicone ice cube forms, GENTLY easy the chocolates out of the forms, they will just pop out - plate up and amaze your guests with these divine triumphs !