Preheat oven to 375. Line a baking sheet with parchment paper.
In a large bowl, combine brownie mix, eggs and oil. Stir for about 2 minutes until dough forms. You can also do this with your electric (or handheld) mixer,
Using a medium cookie scoop, (about 2-3tbsp of dough) scoop the dough and shape into balls.
Place on prepared baking sheet at least 1 inch apart and bake for 10-12 minutes or until the edges are golden brown. Let cool for 5 minutes before transferring to a wire rack. Cool cookies completely before proceeding.
Spread 1/2 tbsp of peanut butter on the flat side of half of the cookies.
Scoop vanilla ice cream and place on top of peanut butter. Top with a second cookie, pushing down gently. Place the ice cream sandwiches on a cookie sheet and freeze for at least 30 mins or until set.
Store ice cream sandwiches once set in a freezer friendly zip lock bag.