Line a 8x8 square baking dish with plastic wrap. Set aside.
In a heavy bottom saucepan, heat butter over medium-high heat.
When melted, add brown sugar and milk, stirring to combine. Bring to a simmer. When you start to see bubble, time about 3 minutes, stirring constantly. Mixture should be smooth. Do not overheat, it will seperate.
Remove from heat and whisk in peanut butter and vanilla.
Pour peanut butter mixture over powdered sugar in a large mixing bowl or the bowl of a stand mixer fitted with the paddle attachment. You will get the best results using an electric mixer versus hand mixing and pre-sifting your powdered sugar.
Mix until smooth, approximately 4 minutes.
Pour into prepared square baking dish. Pat mini chocolate chips into the top of half of the fudge.
Cover with plastic wrap and refrigerate until firm, approximately 8 hours.
Cut and serve. I prefer to keep my fudge chilled until ready to serve.
If you've tried this recipe, come back and let us now how it was!