Because the alcohol-based flavors diminish when cooked, I generally add liqueurs to desserts after they're cooked. Brew a strong cup of coffee for best results in baking To get the most flavor when using brewed coffee in a recipe, I almost always use espresso because it has a strong, dark flavor. But that's at the restaurant, where I have access to an espresso machine. At home, I use regular coffee at double-strength. For example, most coffee makers suggest using 1 rounded teaspoon for every 6 ounces of water, so I use 2 rounded teaspoons.
Brewed coffee works best to bolster other forms of coffee.
I find that using brewed coffee as the only coffee flavoring in a recipe doesn't pack enough coffee flavor, so I almost always use it in conjunction with another form of coffee, a sort of coffee reinforcement. Go ahead and use decaf if you prefer. The process of decaffeination deprives coffee beans of some of their aroma and flavor, but a good brand of decaffeinated will work fine in these recipes. In fact, the three flavors together are divine. I also like to pair coffee and caramel because they're both strong flavors that play well off each other, as in the espresso brittle recipe that follows.