Line a 9x9-inch square pan with parchment paper, allowing the parchment to extend up the sides of the pan for easy removal.
Melt the chocolate mixture.
Place the semi-sweet chocolate chips and sweetened condensed milk in a large microwave-safe bowl. Microwave for 1 minute.
Stir until smooth.
Stir the chocolate and sweetened condensed milk thoroughly until the chocolate chips begin to melt and the mixture becomes smooth. If needed, microwave for an additional 30 seconds, then stir again until fully melted and combined.
Add flavoring and pecans.
Stir in the vanilla extract, salt, and chopped pecans until evenly incorporated.
Create the first fudge layer.
Quickly pour half of the chocolate fudge mixture into the prepared pan. Spread it evenly into the bottom of the pan.
Melt the caramel.
Place the unwrapped caramels and heavy cream in a medium microwave-safe bowl. Microwave in 30-second intervals, stirring between each interval, until the caramel is completely melted and smooth.
Add the caramel layer.
Pour the melted caramel mixture over the first fudge layer. Spread it evenly across the surface.
Add the remaining fudge.
Drop the remaining chocolate fudge mixture over the caramel layer in spoonfuls. Gently spread it into an even layer, taking care not to disturb the caramel layer excessively.
Top with pecans.
Press additional chopped pecans into the top of the fudge.
Chill the fudge.
Refrigerate the fudge for 2 to 3 hours, or until firm.
Cut the fudge.
Once the fudge is cold and firm, lift it from the pan using the parchment paper. Transfer it to a cutting board and cut into 16 pieces.
Store and serve.
Store the fudge in an airtight container. For best texture, refrigerate the fudge and allow it to sit at room temperature briefly before serving.
Notes
To make this recipe gluten-free, use certified gluten-free semi-sweet chocolate chips, as some brands may be processed in facilities that handle wheat.Confirm that the sweetened condensed milk, vanilla extract, caramels, heavy cream, salt, and pecans are labeled gluten-free or free from gluten-containing additives.Check the caramel packaging carefully, as ingredients and manufacturing practices may vary by brand.If serving this fudge to someone with celiac disease or a gluten sensitivity, avoid using shared utensils, bowls, or cutting boards that may have touched gluten-containing foods.Store the finished fudge separately from cookies, cakes, or other gluten-containing desserts to prevent cross-contamination.