Line an 8×8 inch square baking pan with foil and spray it with nonstick cooking spray. Setting it aside will make it easier to remove the fudge later.
Melt the butter in a saucepan over medium-low heat. Stir it gently until fully melted, being careful not to let it brown.
Add the brown sugar and half and half to the melted butter. Heat this mixture over medium, stirring constantly until everything is well combined.
Once combined, allow the mixture to come to a boil. As it starts bubbling, begin timing for two minutes. Keep stirring to prevent burning.
After two minutes, you'll notice the mixture has thickened and is bubbling nicely. Remove it from the heat and let it cool slightly.
Stir in the creamy peanut butter and vanilla, mixing until it's completely smooth and well combined.
In a large mixing bowl, place the powdered sugar. Pour the hot peanut butter mixture on top. Mix everything together until it’s fully combined and silky.
Pour the fudge mixture into the prepared pan. Use the back of a spoon to gently press it into an even layer. This will help achieve a nice finish on top.
If you’re in a hurry to serve the fudge, pop it into the freezer for about an hour. Otherwise, refrigerate for at least two hours or overnight for the best results.
Once set, lift the fudge out of the pan using the foil. Peel off the foil and place the fudge on a cutting board. Cut it into 36 even squares for serving.
Store any leftover fudge in an airtight container in the fridge to maintain freshness.
