Booze deserves just as much of a place in your baking dish as it does in your cocktail glass.  Whether you add the smoky, intense flavor of a spiced rum to banana bread pudding or a rich porter to Irish-style fruit cake, alcohol can give flavor, moisture, and a tender crumb to your baked goods. 

Here's how to use it:

Flavor

A good rule of thumb is to use the same amount of alcohol as you would use an extract.  Bourbon is often aged in oak barrels, giving it a smoky vanilla flavor.  Think of it like vanilla/almond extract combo, and add into pie filling, cake mix, and cookie dough.  Red wine, port, or brandy adds a nice sweetness, along with the winey flavor, great for gingerbread, chocolate cake, and syrupy glazes. 

And remember, like any other ingredient, quality matters.  Don't skimp and use the cheap stuff here—a dash of good bourbon can add nice, rich flavor while a splash of lower end stuff will just taste bitter. 

While some recipes include the alcohol in the baking mix, if you want the real strength of booze in your baking, use it without cooking it: add alcohol some to simple syrup to soak the cake layers in or fold a little into frosting, whipped cream, or glaze for the final topping. 

Texture

Beyond flavor, alcohol can also affect the texture of your baked goods.  Adding a splash of vodka into pie dough can help create a super flaky dough—unlike water, vodka doesn't develop as much gluten in the pie dough.  The same goes with tart and shortbread dough—for flaky results, add in a splash of vodka. 

Moisture

In some recipes, booze plays the major liquid part, like this wine cake.  The wine not only gives it a sweet, boozy flavor, but also a nice, moist bite.  This works especially well in cakes that are soaked after cooking, like sticky toffee pudding (make it with bourbon) or coconut cake (try coconut rum).