Begin by preheating your oven to 325°F (163°C).

Prepare three 8x2 inch round cake pans by greasing and flouring them thoroughly. For extra ease in releasing the cakes, line each pan with a round of parchment or wax paper.

In a mixing bowl, combine the cake mix, flour, and sugar, blending them for about 30 seconds to ensure even distribution.

In a separate bowl, whisk together the water, eggs, canola oil, and vanilla. Then add the peanut butter, mixing until smooth.

Add the wet mixture to the dry ingredients, blending on medium speed for 2 minutes. Pause after the first minute to scrape down the sides and bottom, then resume mixing for the remaining time.

Pour the batter evenly into your prepared pans. Place in the oven and bake at 325°F. Start checking for doneness at around 23 minutes; the cake should spring back slightly to the touch, and a toothpick inserted in the center should come out clean or with just a few crumbs. You may also notice the cake pulling away from the sides of the pan.

Baking at a lower temperature, 325°F instead of the usual 350°F, helps to reduce doming on the cakes for a more level surface.

Slice the butter and place it in your mixer bowl. Blend on low to medium speed until it becomes creamy and smooth. Add the peanut butter and mix until fully combined.

Next, add the cream cheese in small pieces while mixing at low to medium speed until everything is well incorporated. (If using a hand mixer, you may need to soften the cream cheese further before starting.)

Add the vanilla extract and gradually sift in the powdered sugar, mixing on low speed until all sugar is integrated. Increase the speed to medium and whip until the frosting is light and fluffy. Avoid overmixing, as this may make it too soft; if needed, chill briefly to firm it up.

For optimal piping, use the frosting while slightly cool. It can also be prepared in advance and stored in the refrigerator. When ready to use, let it warm to room temperature without microwaving, then re-mix briefly.

Since the ganache is only for the top of the cake and not between layers, we made a smaller quantity. Adjust as necessary, using equal parts chocolate and cream.

In a microwave-safe bowl, combine the chocolate and heavy cream. Microwave for 30 seconds, then stir. If needed, microwave for another 15 seconds, stirring in between. Continue this process until almost all the chocolate has melted, with just a few soft bits remaining. Let it sit for a few minutes to finish melting.

Allow the ganache to cool and thicken for 15-20 minutes. To check if it’s ready, test a small drip along the inside of the bowl—if it flows halfway down, it’s perfect. If it runs too far, it needs to cool a bit more.

Transfer the ganache to a disposable piping bag and snip a small tip to control the flow.

Position the first layer of cake on your cake stand or base and spread an even layer of Peanut Butter Cream Cheese Frosting over it. Sprinkle chopped peanut butter pieces for added texture.

Place the second cake layer on top, repeating the frosting and peanut butter pieces. Add the final layer and cover the cake with a crumb coat, then refrigerate for 10-15 minutes to set.

After chilling, apply a smooth final coat of frosting. Use a warm metal bench scraper for a flawless finish, if desired. This cream cheese frosting smooths well, so this step is optional.

Chill the cake while preparing the ganache. Once ready, apply the ganache drip around the cake’s top edge, allowing it to cascade over the sides. Finish by filling in the top with spirals or designs of your choice.

To garnish, halve mini peanut butter cups and place them decoratively along the cake’s edge. If they soften, chill briefly before slicing for cleaner cuts.