Before you dive into cooking, make sure your workspace is clean and organized. Lay out all your ingredients and tools so you can easily reach them as you cook.
In a medium saucepan over medium heat, melt the 4 tablespoons of butter. Allow it to become bubbly but not browned, which will add flavor to your pralines.
Once the butter is melted, add the 3/4 cup of firmly packed brown sugar, 3/4 cup of granulated sugar, and 3/4 cup of half-and-half to the saucepan. Stir continuously until the sugars dissolve completely.
Raise the heat to medium-high and bring the mixture to a boil, stirring constantly. You’ll want to cook it until it reaches the soft ball stage, which is about 236°F (113°C) on a candy thermometer.
Once the mixture has reached the correct temperature, remove it from the heat. Stir in the 2 cups of pecans and 1 teaspoon of vanilla extract. Mix well until the nuts are evenly coated.
Using a spoon, drop heaping tablespoons of the mixture onto the parchment paper-lined cookie sheet. Leave space between each praline as they will spread slightly while cooling.
Allow the pralines to cool completely at room temperature. This usually takes about 30 minutes. Once set, they should have a firm yet slightly soft texture.