Line 2 large baking sheets with wax paper and set aside.
In a large heavy-bottomed saucepan, combine 3 cups granulated sugar, 1 cup buttermilk, 3 tablespoons light corn syrup, 1 teaspoon baking soda, and 1/2 teaspoon salt.
Heat, while stirring, over medium heat until sugar dissolves Southern Buttermilk Pecan Pralines - Bakers Table. Stop stirring and cook to 236°F (soft ball stage), occasionally brushing down sides with a pastry brush dipped in warm water.
Remove from heat and immediately add 3 tablespoons butter, 1 teaspoon vanilla extract, and 2 cups toasted pecan halves.
Beat vigorously with a wooden spoon until the mixture begins to thicken and loses its glossy appearance (about 2-3 minutes).
Working quickly, drop spoonfuls of the mixture onto the prepared wax paper, creating 2-3 inch rounds.
Allow to cool completely at room temperature for 30 minutes until set.
Store in an airtight container at room temperature for up to 1 week.