Make sure your eggs are room temperature - don't use cold eggs. The one time this recipe didn't work as I expected was the one time I used cold eggs.
For the coffee liqueur I used Kahlua. If you don't want to use a liqueur, I would suggest using the same amount of cooled coffee.
The recipe goes quickly once you start, so measure and lay out all the ingredients in order of use.
If you are feeling a little adventurous and spicy, add a pinch or two of cayenne to the recipe. The spice will intensify the taste of the chocolate without providing too much heat to the dish.
I use a creme brulee set from Chicago Metallic to make these cakes. It includes 4 4-oz ramekins, a rack to set them on, and a baking pan to put them in.
Adapted from Fine Cooking, Molten Chocolate Cakes with Raspberries.