Instructions
- Line an 8x8 inch baking pan with parchment paper, leaving an overhang on the sides.
- Melt the butter in a medium saucepan over medium heat, cooking until it turns golden brown and has a nutty aroma. Remove from heat and let cool slightly.
- Add the sugar and heavy cream to the browned butter and cook over medium heat, stirring constantly, until the sugar is dissolved and the mixture comes to a rolling boil.
- Continue to boil for 5-7 minutes, stirring constantly, until the mixture reaches 235°F (113°C) on a candy thermometer.
- Remove from heat and stir in the peanut butter, vanilla bean paste, and fleur de sel until smooth.
- Melt the dark chocolate in a double boiler or microwave.
- Pour half of the peanut butter fudge into the prepared pan. Drizzle the melted dark chocolate over the fudge and swirl with a knife or toothpick.
- Pour the remaining peanut butter fudge over the chocolate swirl and spread evenly.
- Let cool completely at room temperature before cutting into squares.
