Prepare the Pecans: Arrange pecan halves in clusters of 3-4 on parchment-lined baking sheets.
Make the Caramel: In a heavy-bottomed saucepan, combine butter, brown sugar, corn syrup, and sweetened condensed milk. Cook over medium heat, stirring constantly, until the mixture comes to a boil.
Cook the Caramel to Perfection: Continue cooking, stirring constantly, until the caramel turns a golden brown color and thickens, about 10-15 minutes. Be careful not to burn the caramel. It should coat the back of a spoon.
Add Vanilla: Remove from heat and stir in vanilla extract.
Pour Over Pecans: Immediately spoon the caramel over the pecan clusters, covering them completely.
Cool Completely: Let the turtles cool completely at room temperature, about 1-2 hours.
Melt the Chocolate: In a double boiler or microwave, melt the chocolate chips until smooth.
Dip the Turtles: Dip each turtle in the melted chocolate, coating it completely. Place the dipped turtles back on the parchment-lined baking sheet.
Optional: Sprinkle with Sea Salt: Sprinkle with sea salt flakes, if desired.
Let Set: Let the chocolate set completely, about 30 minutes in the refrigerator or 1-2 hours at room temperature.
