Mix peanut butter, sweetened condensed milk and vanilla extract in a large mixing bowl.
Add the Bisquick and combine, mixture will be thick.
Separate dough using a large cookie scoop or 1/4 measuring cup and roll into balls.
Flatten about halfway using fork tines.
Cover and refrigerate dough for at least 2 hours but up to 5 days.
Line baking sheet or prep with cooking spray. Space dough at least 2 inches apart.
Bake at 350 for 13-14 minutes.
Let cookies cool on baking sheet for 10 minutes before serving.
