Begin by toasting the pecans: pour the 2 ½ cups into a large skillet and set over medium‑high heat. Stir occasionally until the pecans darken just a bit and smell fragrant—this usually takes only a few minutes.

Meanwhile, prepare two large cookie sheets: line each with parchment paper and spray lightly with cooking spray. Once the pecans are toasted, arrange them into clusters on the sheets—three pecans per cluster works well. Leave about an inch of space between each cluster to allow for spreading.

Make the caramel: in a medium‑sized saucepan, melt the ½ cup butter over medium‑high heat. Then add the 1 cup brown sugar, ½ cup light corn syrup, and 7 oz sweetened condensed milk. Increase the heat slightly and stir continually until the mixture reaches ~235‑240 °F (you can remove at ~234 °F as it will continue to rise slightly).

Remove the caramel from heat and stir in the ½ teaspoon vanilla.

Quickly drizzle about 1½ teaspoons of caramel over each pecan cluster—be sure the caramel touches all the nuts in the cluster so that it acts like glue and holds them together. The caramel will begin to set up so you’ll want to work efficiently.

In a microwave‑safe bowl place the 12 ounces of milk chocolate chips. Microwave for 30 seconds, stir; if not yet smooth repeat in short intervals until fully melted. Then stir in the ½ teaspoon shortening—this helps the chocolate become smoother and more spreadable.

Spoon about 1½ teaspoons of the melted chocolate over each caramel‑nut cluster. Use the back of the spoon to swirl the top of each cluster so it looks pretty.

Allow the chocolate to set up and harden (at room temperature) before serving. Once hardened you can enjoy them immediately or transfer to an airtight container for storage.