Geode Cake

The seemingly-endlessly-trending geode cake! 😉 

I fiiinally found a picture of the geode cake I tried with a friend back in the day as a clueless newbie baker…and somehow thought just using colored rock candy would work…? No lies, it looked kinda  awful. So if you’re reading this with plans to make a geode cake you’re way ahead of me! 😉  Learn from my mistakes and color the rock candy AFTER you put it on the cake!

 (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 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 - 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


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 slowly 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, on a low speed. Add in vanilla and oil, 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!

Cream Cheese Buttercream Frosting:  
8 oz (one package) cream cheese, softened
16 Tablespoons (two sticks) butter, softened
6-7 c powdered sugar  
2-4 Tablespoons milk
1 T clear vanilla extract
1/4 t. salt (if using unsalted butter)
Save and add later if desired – few drops of teal gel food color for the cake filling!
Beat together softened cream cheese and butter; slowly add in powdered sugar alternating with milk until frosting reaches desired consistency. Add vanilla and salt if needed and beat until well combined.

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)
- Silver lustre dust or edible paint
- Rock candy crystals (- I also found a pair of tweezers handy for placing rock candy into the ‘geode’ base)
- Teal food color + few more drops clear vanilla extract to fade the color toward the outside of the geode
- Edible silver leaf (I bought mine from Gold Leaf Factory via Amazon!)
- Silver sprinkle mix (if you want to add sprinkle ‘stars’ to the cake)

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. (I wanted a bit more liqueur kick to my cake layers, so I used a squeeze bottle to infuse each one with a few tablespoons of the rum/curacao/grenadine mix above. Optional but recommended!)
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, or add a small ‘rim’ of white frosting and fill with teal 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. 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 rock candy in place.  
Press rock candy crystals into the frosting to cover the base of the geode ‘hole.’ I found tweezers handy for reaching the deeper parts. 
To color the geode, use a bit of teal gel color with a bit of vanilla extract (so it dries more quickly) and brush into the center/deepest part of the geode. Add a lot of color at the center and continue to thin the color with vanilla extract to make it progressively lighter toward the outer edges. With some lustre dust + rum or edible silver paint, cover the outer edge of the geode, brushing it in toward the center a bit if you’d like.

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!
Finish it off with a few extra pieces of silver leaf and some silk flowers 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!

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