Start by preheating your oven to 350°F (175°C). Grease a 9x13 inch baking pan with a bit of vegetable oil or line it with parchment paper for easy removal later.
In a large mixing bowl, combine the vegetable oil and granulated sugar. Whisk them together until fully blended. Add in the cocoa powder, mixing until incorporated.
Crack in the eggs, one at a time, whisking well after each addition. Stir in the vanilla extract and water to create a smooth mixture.
Gently fold in the all-purpose flour using a spatula. Be careful not to overmix; just stir until you can no longer see any flour streaks. Finally, fold in the chocolate chips for an extra chocolatey treat.
Pour the brownie batter into the prepared pan, spreading it evenly. Bake in the preheated oven for about 25-30 minutes, or until a toothpick inserted into the center comes out with a few moist crumbs. Allow the brownies to cool completely in the pan.
In a separate mixing bowl, combine the sweetened condensed milk, peanut butter, and ½ teaspoon of vanilla extract. Stir until smooth and well combined.
Gently fold in the whipped topping until everything is evenly mixed. This will create a light and fluffy peanut butter layer that pairs perfectly with the brownies.
Once the brownies have cooled, spread the peanut butter ice cream mixture over the top evenly. Sprinkle the chopped peanut butter cups on top for a delightful crunch and added flavor.
Place the assembled brownies in the freezer for at least 2 hours to firm up the ice cream layer. Once set, cut into squares and serve chilled. Enjoy your delicious Peanut Butter Ice Cream Brownies!
