Prepare the Pan: Line an 8×8 inch baking dish with parchment paper.
Toast Pecans: Toast pecans in the oven at 350°F (175°C) for 5-7 minutes.
Make the Fudge Base: Melt butter in a saucepan. Add heavy whipping cream, brown sugar, granulated sugar, salt, and cinnamon. Bring to a boil, then simmer for 5 minutes.
Cool and Add Vanilla: Remove from heat, cool for 5 minutes, then stir in vanilla extract.
Incorporate Powdered Sugar: Gradually beat in powdered sugar until smooth.
Add Pecans: Fold in toasted pecans.
Set the Fudge: Pour fudge into the prepared baking dish. Let cool to room temperature, then refrigerate for at least 2 hours.
Cut and Serve: Cut into squares and enjoy!
