Line an 8×8-inch pan with parchment paper and set aside.
In a medium saucepan over medium heat, melt butter. Add brown sugar and half & half. Stir well and bring to a boil.
Allow it to boil without stirring for 1 minute and 45 seconds.
Remove from heat and stir in peanut butter and vanilla until smooth.
Pour the hot mixture into the bowl of powdered sugar. Beat with an electric mixer until completely smooth.
Transfer to the prepared pan and spread evenly. Let cool completely at room temperature until firm.
Slice into small squares and enjoy.
