Melt 1.5 tablespoons of unsalted butter in a skillet over medium heat. Add the pecan halves and toast for 4-5 minutes until browned.

Line an 8x8-inch baking pan with parchment paper and grease it lightly. In a saucepan, brown 3 tablespoons of unsalted butter.

In a heatproof bowl over simmering water, combine the sweetened condensed milk, white chocolate, and browned butter. Stir gently for 5-7 minutes until smooth.

Remove from heat and whisk in vanilla extract, salt, and ground cinnamon. Fold in the toasted pecans.

Pour the mixture into the prepared baking dish, smooth the top, and refrigerate for at least 2 hours until firm.

Once set, loosen the fudge from the pan and cut into squares. Store in an airtight container in the refrigerator.