Place oil in a medium-size bowl and microwave for approximately 1 minute. Stir in PBfit and vanilla extract until smooth and creamy. Fold in powdered sugar one cup at a time and continue folding until a smooth dough forms. If your dough becomes too dry add 1-2 Tbsp of water to help it smooth out.
Spread fudge into a parchment lined 8 by 8-inch pan. Chill for at least 2 hours. Cut into 1-inch cubes. Store in an airtight container in the refrigerator. Enjoy!