Halloween Sprinkle Geode Cake

The seemingly-endlessly-trending geode cake! 

The seemingly-endlessly-trending geode cake! 😉
After making a couple of more traditional-style geode cakes (and finally getting one to turn out), I’m finally also jumping on the sprinkle geode bandwagon! These geodes are SO fun, and honestly they make for much easier cakes to cut into and eat! (Who really actually likes crunching down on rock candy in their cake slice?) Recipe + instructions below! 

(Disclosure: As a way to keep my kitchen stocked with butter, sugar, and flour I am a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for me to earn a commission by linking to Amazon.com and affiliated sites.
My posts often contain affiliate links. If you click a link and make a purchase, I may receive a commission at no extra cost to you!) 

Vanilla Cake Layers:

Note - this is a slightly-simplified layer cake recipe from ChelSweets.com - I highly recommend checking out her site if you haven't before; it's amazing!! 
3 1/4 cup all-purpose flour
3 cup  granulated sugar
2 1/2 teaspoon baking powder
1 teaspoon  salt
1 cup unsalted butter (or 2 sticks) room temperature
2 teaspoons clear vanilla extract
5 eggs 
1 1/2 cups buttermilk, room temperature (or buttermilk powder with water is an option if you can’t find liquid buttermilk at your grocery store!)
1/8 cup (28 grams) vegetable oil
4-5 large drops purple food coloring (I used Americolor Electric Purple gel color)

Instructions:
Preheat oven to 350°F. Line four 7 inch pans (for taller layers) or three 8-inch cake pans with parchment rounds, and /or grease with non-stick or baker’s floured cooking spray.
Mix together all dry ingredients (flour, baking powder, sugar, and salt) in a stand mixer with a paddle until fully combined. 
Mix chunks of room-temperature butter into the dry mix, on a low speed. Continue to mix until no large chunks of butter remain, and the mixture becomes crumbly. 
Pour in eggs and mix on low until just incorporated.  Mix in the buttermilk in two installments, keeping the mixer speed on low. Add in vanilla, oil, and gel color, and mix at a low speed until fully incorporated. Scrape down the sides of the bowl with a spatula, then beat on medium speed for about 30 seconds.

Divide batter evenly between the prepared cake pans (I find a kitchen scale helpful for this part). This guarantees your layers will bake to be the same height.

Bake for 35-37 minutes if using 8-inch pans, or 37-38 minutes for 7-inch cake pans (or until a toothpick comes out clean). Allow cake layers to cool for 10-15 minutes on a wire cooling rack before removing from pans – it helps to run an offset spatula or knife around the perimeter of the pan first. Cool completely before frosting. Set in the fridge or freezer to accelerate the cooling process if desired.
Once the layers have fully cooled, the caramelized bits can be trimmed from the sides / top of the cake using a serrated knife if desired. Be sure the layers are completely cooled or chilled before trimming. If you try to trim the layers while they’re still warm, they will crumble apart.

While you’re waiting…make your frosting!

Black Chocolate Cream Cheese Buttercream Frosting
8 oz (one package) cream cheese, softened
16 Tablespoons (two sticks) butter, softened
5 ½ -6 cups powdered sugar
1 cup black cocoa powder
4-6 Tablespoons milk
1 T vanilla extract
1/4 t. salt (if using unsalted butter)
- 2-3 drops black gel food coloring
Beat together softened cream cheese and butter; slowly add in powdered sugar alternating with cocoa powder and milk until frosting reaches desired consistency. Add vanilla, food color, and salt if needed and beat until well combined.
Note – frosting’s color will deep if left to sit for several hours or overnight – this lets you get a deeper color with less gel food coloring!

Additional Supplies/Equipment:

- 1 8- or 10 -inch cardboard cake circle (I prefer Wilton’s center-punched circles)
- small paring knife (for making the ‘geode’ cut into the cake)
- Small offset spatula
- small new or food-safe paintbrush
- Cake leveler, cake turntable, large offset spatula, and pastry cutter/bench scraper - not all 100% necessary but incredibly helpful! (Here’s a link to the cake turntable I use)
- Edible silver leaf (I bought mine from Gold Leaf Factory via Amazon!)
- Sprinkle mix of your choice – I did mine close to Halloween, so I used FancySprinkles’ ‘Goosebumps’ Halloween mix!
- Silicone skull molds (I used this 3D mold set off of Amazon and loved it!) and candy melts – colors are up to you; I used purple and green candy melts from Wilton!
- Edible glitter (if desired) – I love FancySprinkles’ Prism Powder!

Assembly:
Once your cakes are cool, level them (if needed/desired; these cakes usually bake fairly flat so I didn’t trim much from the tops). This can be done with a cake leveler or a large serrated knife and a ruler.
Place a smear of frosting on your large cake circle (to keep the cake from sliding while you decorate it) and center your large first cake layer in the center of the circle. Spread the layer with frosting. Add your next cake layer on top, and repeat the process with your remaining cake layers.
Now you're ready to crumb-coat . If you're unfamiliar with crumb-coating, it's just what it sounds like – spreading a thin layer of frosting over the entire outside of the cake tiers to keep crumbs out of your final layer.
Once your crumb coat has set (this takes about 5-10 minutes in the fridge), add your final layer of frosting and smooth. I like to use a large offset spatula and pastry cutter/bench scraper for this part.

Now the FUN part! Carve your ‘geode’ shape! I shot for a few inches into the top and 1” from the cake base for the ends, and made two cuts connecting my end points. I made the opening deepest toward the center, probably 1 ½” at its deepest. I also cut a couple smaller shapes – up to you! Feel free to eat the cake scraps!
With a small offset spatula, re-crumb-coat the geode ‘hole.’ This will keep crumbs in and hold your sprinkles in place.
Press sprinkles into the frosting to cover the base of the geode ‘hole.’ I found tweezers and spreading crisco on a fingertip handy for reaching the deeper parts.
I also found it easiest to start with the larger sprinkles and fill in around them.

Rim the outside of the geode with bits of edible silver leaf – I tried a few methods for transferring it, because it’s VERY fragile and a bit finicky. Tearing off and moving bits at a time with a dry paintbrush or Q-tips has been my favorite method so far!
Melt a handful of candy melts (30-50% power in the microwave works well) and transfer to the skull mold; refrigerate 5-10 minutes to set before removing.
Finish it off with your colored skulls and a few extra pieces of silver leaf if you’d like – and you’re done!

Seriously; find someone to give you a high-five on your kick-butt cake! DM me on Instagram if you can’t find someone quickly!

Make this recipe? Let me know how it went - or find me on Pinterest or on Instagram and tag @IntensiveCakeUnit in your photo!



Leave a Comment

Your email address will not be published. Required fields are marked *