Combine the sugars, milk and butter in a medium-sized pot and cook over a medium-high heat, stirring occasionally.
When the mixture comes to a boil, add the pecans and start stirring constantly. Let the syrup boil for 3 minutes, until the syrup registers 238-240° F on a candy thermometer.
Remove the pan from the heat, add the vanilla.
Continue to stir constantly. The syrup will become creamy and cloudy. As you stir, you will notice the syrup thicken. When you start to feel the syrup get grainy, the pralines are ready.
Working quickly, drop by spoonfuls onto parchment paper. Let cool for at least 10 minutes before eating.
Notes
Expert Tips
Prep Ahead: Before you even turn on the stove, make sure all your ingredients are measured and within easy reach. Praline-making is a fast process, and you don't want to be scrambling for that last ingredient.
Follow the Recipe: Stick to the ingredient ratios and steps detailed in the recipe. Deviating can result in pralines that are too soft, too hard, or just not quite right.
Choose the Right Saucepan: A medium, heavy-duty 2-quart saucepan is ideal for praline-making. Its size and build ensure even heat distribution.
Hot Water Trick: Keep a kettle of hot water nearby. If your praline mixture hardens too quickly, a tablespoon of hot water can bring it back to the desired consistency. Just add and stir vigorously.
Be Speedy: Once the praline syrup starts to thicken, work quickly to form your pralines, as the mixture will harden in no time.
Safety First: The praline mixture gets incredibly hot, so exercise caution while stirring. Use a cutting board under your parchment paper to protect your countertops from potential burns.