Toast the Pecans:
In a large skillet over medium-high heat, toast the pecan halves for a few minutes until they become fragrant. Stir occasionally to prevent burning. Remove from heat and set aside.
Prepare Baking Sheets:
Line two large baking sheets with parchment paper and lightly spray with nonstick cooking spray. Arrange the toasted pecans into clusters, typically three pecans per cluster, leaving about an inch of space between each group.
Make the Caramel:
In a medium saucepan, melt the butter over medium-high heat. Add the brown sugar, corn syrup, and sweetened condensed milk. Stir continuously until the mixture reaches 235°F–240°F (soft-ball stage) on a candy thermometer. Remove from heat and stir in the vanilla extract.
Assemble the Clusters:
Spoon approximately ½ tablespoon of the caramel over each pecan cluster on the prepared baking sheets. Allow the caramel to set for a few minutes.
Melt the Chocolate:
In a microwave-safe bowl, combine the milk chocolate chips and shortening (if using). Microwave in 30-second intervals, stirring after each, until the chocolate is fully melted and smooth.
Top with Chocolate:
Spoon about ½ tablespoon of the melted chocolate over each caramel-covered pecan cluster, ensuring the caramel is covered. Let the clusters sit at room temperature or refrigerate until the chocolate is set.
