In a small pan, add peanut butter and butter over low heat and cook until meltedand smooth.
Add the sugar and protein powderand mix until smooth. Remove from the heat and stir invanilla extract.
Place the fudge mixture into a small bakingpaper-lined baking dish evenly and with a spatula, smooth the top surface.Freeze for about 30-45 minutes or until set completely.
Carefully, transfer the fudge onto a cuttingboard with the help of parchment paper.