This is really easy.
Get some good quality oil ( I used olive, but any other well flavoured oil would do ) and a head of smoked garlic.
Peel lots of the heavily smoked outer skins of the garlic and put them in a jar. Crush 3 or 4 of the cloves and add these to the jar.
Top it up with your oil, and leave it in a dark cupboard for a month or so.