Ganache

3 tablespoons corn syrup
6 ounces heavy cream
12 ounces dark chocolate, chopped into small pieces (or 1 bag chocolate chips)
1/2 teaspoon vanilla extract

In a small saucepan combine the corn syrup and heavy cream. Bring to a simmer and add the chocolate. Stir until smooth. Remove from the heat and add the vanilla extract.

You will probably want to do this with a double boiler: mix the ingredients in a glass bowl set on a pan of simmering water.