For the Brownie Cake Layers:

1. Preheat & Prep: Preheat oven to 325°F. Prepare (3) 6 inch cake pans or (2) 8 inch cake pans with baking spray or a homemade pan release. You can also use parchment paper rounds at the bottom of the pans for extra insurance.
2. Melt Butter: In a microwave-safe bowl, microwave the butter at 15-30 second intervals until completely melted. Set aside.

3. Combine the Ingredients: In a large mixing bowl, add the brownie mix, eggs, melted butter, and water. Stir until the batter is almost combined—don’t over-mix.

4. Chocolate Chips: Add the chocolate chips to the brownie batter and gently fold them in with a spatula until evenly distributed.

5. Scoop into Pans: Scoop batter into prepared cake pans. If you can, use a food scale

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   to evenly distribute batter between pans for consistent cake layer size. For thinner cake layers, use the (3) 6 inch pans. For thicker cake layers, use the (2) 8 inch pans. 

6. Bake: Bake for 26-28 min for 6 inch pans, and 30-32 min for 8 inch pans. Check periodically as all ovens bake differently! 
7. Cooling: Let brownie cake layers cool completely in the pans. 
8. Storage: Double wrap your cake layers in plastic wrap and freeze for up to 3 months. When you’re ready to decorate, simply take out and frost straight from frozen—no need to thaw!

For the Chocolate Fudge Frosting:

1. Whip the Butter: Start by adding the room temperature butter to a stand mixer, fitted with the paddle attachment. Mix the butter on medium-high for 30 seconds-1 minute, scraping the sides of the bowl at least once during this time.
2. Vanilla & Salt: Add the vanilla extract and salt.
3. Start Heavy Cream: Add 2 tablespoons of heavy cream or milk and continue mixing until incorporated. Scrape the bowl.
4. Melt Chocolate Chips: Melt the chocolate chips in a microwave-safe bowl, stirring every 20–30 seconds until smooth, then set aside.
5. Powdered Sugar: Lower mixer speed to the lowest setting, and start adding the powdered sugar in 1-2 cup increments. Add a tablespoon of heavy cream or milk between each.
6. Mix It Up! Slightly increase the mixer speed to help blend these ingredients, but do not turn on too high or you will whip too much air into the buttercream.
7. Cocoa Powder: Add the unsweetened cocoa powder.
8. Reminder: Scrape the sides and bottom of the mixing bowl to make sure all of ingredients are incorporated and to avoid any clumps of butter or powdered sugar.
9. Add Melted Chocolate Chips: Add the melted chocolate chips into the chocolate buttercream.
10. Last Step: Mix on low-medium until all ingredients are incorporated, this could take a few minutes. At this point you should have perfectly smooth, chocolate fudge frosting!