Louisiana pralines are one of the most difficult confections to make consistently at home. Unlike European pralines, which are smooth and glossy, Louisiana pralines are grainy and opaque -- a result of controlled sugar crystallization that must happen at exactly the right moment and temperature.
The Target Temperature
Cook the sugar mixture to 236-240 degrees Fahrenheit -- the soft ball stage on a candy thermometer. Below 234 and the pralines will be too soft and sticky. Above 242 and they will set too hard and become brittle. A two-degree window sounds unforgiving, and it is. Use a reliable candy thermometer and watch it closely in the final stages of cooking.
The Beating Stage
Remove the pan from heat and let it cool to 150 degrees before stirring. Then beat vigorously with a wooden spoon until the mixture loses its gloss and starts to thicken. This is when crystallization begins. The moment you see the texture change, work quickly -- drop the pralines by spoonful onto parchment paper before the mixture sets in the pan.
Humidity Is the Enemy
Pralines should never be made on a humid day. Humidity slows the crystallization process and results in pralines that are sticky, soft, and never set properly. In Louisiana, this means praline-making is best done from October through February when humidity is lowest.