She uses Foremost buttermilk, which is thick and tangy, but it is sometimes difficult to find. You can certainly use any brand of buttermilk that's available in your area.
In a heavy pot at least four and one-half inches deep, mix the buttermilk, sugar, baking soda and salt and stir until the sugar is dissolved. Place the pot over medium heat and cook, stirring constantly, until mixture turns brown and almost reaches the soft-ball stage of 232 degrees, about 35 minutes. Remove the pot from the heat.
Add the butter, pecans and vanilla extract and beat until the mixture is glossy and thick. Spoon onto greased waxed paper. Cool completely. Store in an airtight tin or plastic storage bag.
Makes 3 dozen small pralines