Make the Cake Layers:

1. Preheat oven to 350°F (177°C). Line 3 or 4 8-inch (20 cm) round cake pans with parchment paper rounds, then grease the bottom and sides with nonstick spray. Place the cake pans on a large baking sheet, so that when you bake the cakes you can transfer the pans to the oven all at once. Set aside.
2. In the bowl of a stand mixer, combine the sugar, cake flour, baking powder, baking soda, and salt. Mix with the paddle attachment on low speed for 30 seconds to combine.
3. With the mixer running on low speed, slowly add the chunks of butter to the dry ingredients. Don't do it all at once to prevent splattering. Beat on low speed until the butter breaks down into very fine crumbs, forming a mixture that resembles sand.
4. In a large bowl or liquid measuring cup with a spout, whisk the buttermilk, oil, eggs, and vanilla until combined.
5. With the mixer running on low speed, very slowly pour the wet mixture into the dry ingredients. Once enough liquid has been incorporated that you can no longer see streaks of flour, increase the speed to medium-low and continue adding the liquid. Stop and scrape the bottom and sides of the bowl as needed. If the batter ever looks lumpy, stop adding liquid and allow the mixer to run for 10-20 seconds to beat out any lumps before adding more. Once all of the liquid has been incorporated, the batter will be thin and smooth.
6. Divide the batter between the pans. If you're making 4 cake layers, pour 525g of batter into each pan. If you're making 3 layers, pour 700g of batter.
7. Bake for 20-30 minutes, or until a toothpick inserted in the center of the cake comes out clean or with a few moist crumbs.
8. Allow the pans to cool for 5 minutes, then carefully invert over a wire rack to release the cakes. While the cakes are cooling, make the crumbs and frosting.

Make the Cake Crumbs:

1. Preheat oven to 300°F (149°C). Line a large baking sheet with parchment paper. Set aside.
2. In a large bowl, whisk the cake flour, sugar, brown sugar, sprinkles, baking powder, and salt until combined. Pour in the melted butter and mix until there are no more streaks of flour and moist crumbs form. Toward the end of mixing, I find it is easier to use your hands.
3. Spread the mixture over the baking sheet, breaking up larger pieces of crumbs into slightly smaller pieces.
4. Bake for 11-16 minutes. Every 3 or 4 minutes into baking, rotate the baking sheet and stir the crumbs so that they bake evenly. The crumbs are done baking when they are just slightly dried to the touch. They will harden significantly more as they cool, so they shouldn't be crispy right out of the oven or they will be rock-hard at room temperature.
5. Allow the crumbs to cool completely as you make the frosting.

Make the Whipped Frosting:

This makes a large batch of frosting, so I recommend splitting the recipe in half and making it two times so as to not overwhelm your mixer.

1. Add the cream cheese, sugar, and vanilla to the bowl of a stand mixer. Whip using the whisk attachment for 3-4 minutes or until light and fluffy. Scrape the bottom and sides of the bowl as needed.
2. With the mixer running on medium-low speed, slowly pour in the cream. Once the mixture starts to thicken, increase to high speed and continue pouring in the cream. Keep whipping until the mixture is stiff.

Assemble & Decorate:

1. Place your bottom cake layer on the plate, cake stand, or board you want to serve the cake on. Then, place that on top of your turnable.
2. Use a mini offset spatula to spread 300g of the whipped frosting on top, then sprinkle on 150g of the cake crumbs. If you made 3 cake layers instead of 4, use 450g of frosting and 225g of the crumbs in between each layer. Leave a 1-inch overhang for the crumbs along the edges, and use your fingers to gently press them into the frosting.
3. Repeat with the remaining cake layers, placing the final layer on upside down so it's extra flat. Apply a thin layer of frosting on top of the cake. It doesn't have to be the full 300/450g- you can eyeball it.
4. Apply a crumb coat to the cake by very lightly frosting the sides. Start by adding a small dollop of frosting to the side of the cake and use a mini offset spatula to spread it around. Continue adding more frosting as needed until all of the sides are covered. Use a bench scraper at a 45-degree angle to smooth it out. Fill any additional gaps as needed with more frosting.
5. Refrigerate the cake for a minimum of 30 minutes. The longer you refrigerate it, the more stable it will be for decorating in the next step.
6. Use an icing spatula to apply a thicker coating of the remaining frosting to the top and sides of the cake. It will be hard to smooth out the cake without digging into the crumb coat if you don't use enough, so don't skimp. Once you've added your frosting, sweep a bench scraper against the side of the cake at 45-degree angle to smooth it out. Do this lightly or you'll scrape off too much frosting. Fill gaps or holes with more frosting as needed.
7. Decorate the cake as desired. Use leftover frosting to pipe on the tops or sides and top with sprinkles.
8. Refrigerate the cake if you're not going to serve it right away. Let it sit out at room temperature for at least 1-2 hours before enjoying for the ideal texture- it's much more soft and moist!