Step 1

Line an 8x8-inch baking dish with parchment paper.

Step 2

To a large, heavy saucepan over medium-high heat, add butter.

Step 3

Melt the butter and continue to cook it until it is a rich, golden brown. Keep a close eye as it cooks, stirring it every few minutes so that it does not scorch the bottom. The butter should smell toasty and have a beautiful nutty color.

Step 4

Reduce heat to medium. To the browned butter, add the sugar and evaporated milk.

Step 5

Bring the mixture to a boil. Leave on the heat until the mixture reads 234°F-238°F on a candy thermometer (about 10 minutes).

Step 6

Once the temperature reaches 234°F, remove from heat. Stir in the white chocolate chips until mostly combined.

Step 7

Fold in the marshmallow fluff and vanilla.

Step 8

Transfer the fudge to the prepared pan. Let it cool for at least 2 hours before cutting and serving.