For those incorrectly stating the alcohol would cook off..... According to the U.S. Department of Agriculture (USDA), baked or simmered dishes that contain alcohol will retain 40% of the original amount after 15 minutes of cooking, 35% after 30 minutes and 25% after an hour. But there’s no point at which all of the alcohol disappears. Baking or simmering an alcohol-containing dish for 2.5 hours will still leave 5% of the alcohol content behind.
This is also backed up by UK scientific studies.