Cake Layer

• Preheat the oven to 350°F (175°C). Grease a 9-inch springform cake pan.
• Combine the cake mix with the milk, oil, peanut butter, and eggs in a large mixing bowl. Beat on low for 30 seconds, then increase the speed to medium and beat for another 60-90 seconds to ensure the ingredients are well mixed, scraping down the sides of the bowl as needed.
• Transfer the batter to the prepared springform pan.
• Bake for 25-30 minutes, or until a toothpick inserted into the center comes out clean or with a few crumbs attached.
• Allow the cake to cool completely.
• Top the cake with the chopped peanut butter cups before placing the cake into the freezer.

Ice Cream Layer

• Whip the heavy cream in a large mixing bowl until stiff peaks form.
• Mix the sweetened condensed milk, peanut butter, and vanilla extract in a separate mixing bowl, until smooth.
• Gently fold the whipped cream into the peanut butter mixture until well combined.
• Spread the peanut butter ice cream mixture over the prepared cake, smoothing the top with a spatula.
• Freeze for at least 4 hours, or until firm.

Chocolate Ganache

• Place the chocolate chips in a heatproof bowl.
• Heat the heavy cream in a small saucepan over medium heat until it just begins to simmer.
• Pour the hot cream over the chocolate chips and allow it to sit for 2 minutes - untouched, then stir until smooth.
• Allow the ganache to cool slightly.
• Remove the cake from the freezer and run a knife around the edge before releasing the side of the springform pan.
• Pour the ganache over the frozen peanut butter ice cream layer, spreading evenly.
• Top the ganache with the chopped peanut butter cups.
• Return the cake to the freezer for another hour, or until the ganache is set.

Optional: Decorate the top of the cake with whipped topping and additional peanut butter cups. Freeze until ready to serve.

To serve, remove the cake from the freezer and let it sit at room temperature for a few minutes to soften slightly.