I prefer to use Camp Coffee when cooking. It's a rich syrupy strong liquid coffee. Alternatively you can use instant coffee mixed with water; 1tsp of instant coffee mixed with 1 tbsp of water is the equivalent of 1tbsp of Camp Coffee.
We made coffee cupcakes using camp coffee, here's the recipe
6oz SR Flour
6oz Caster Sugar
4 tbsp Camp Coffee
1 tub Mascapone
2 tbsp Soft Brown Sugar
Mix together the flour, caster sugar, butter eggs and 3 tbsp of coffee until smooth. Fill 12 muffin cases and bake at 170C (fan) for 25 mins. When cooked remove from tin and allow to cool.
Now make the icing: mix together the mascapone brown sugar and 1 tbsp of coffee until well blended and pipe onto top of cupcakes.
I have recently bought some Wilton piping nozzles and have found them to be marvellous, it's sometimes better to invest in a good product. It's certainly the case here.
This is the nozzle I used for these cakes: