1. Before starting to cook, prepare the items you'll need for the pralines to cool: Lay out a piece of parchment, aluminum foil or a silicone baking mat. Also set out an extra spoon. The pralines will cool quickly after they're finished cooking, so it's important to have these items ready.
2. Combine all the ingredients except for the peanut butter in a medium saucepan that holds at least 4 quarts. Using a smaller pan could cause the mixture to bubble over.
3. Cook the mixture over medium-high heat, stirring occasionally. When it comes to a boil, start stirring constantly. Let it boil for about 3 minutes, until the syrup registers 238°–240°F. on a candy thermometer. During the last 2° of cooking, stir in the peanut butter.
4. Remove the pan from heat immediately and continue stirring. The mixture will become creamy, cloudy and thick. When the mixture starts to get grainy, the pralines are ready.
5. Drop spoonfuls of the mixture onto the parchment, using a second spoon to scrape the candy off the first spoon if necessary. Work quickly, as the pralines will set as they cool. Let the pralines cool and harden for at least 10 minutes. The pralines are best within 24 hours, but they will keep in an airtight container for several days.
* To toast pecans, arrange them in a single layer on a baking sheet lined with parchment paper. Bake at 350°F. until golden and toasty, about 5–10 minutes. Keep an eye on the pecans to keep them from over-browning. Cool. Store in an airtight container if using within a few weeks or in the freezer until you need them.
Adapted from TheKitchn.com