Halloween Sprinkle Slime Cake

My most popular Halloween 'Slime' Cake - with a fun sprinkle twist that shows off the 'Science experiment flask' topper!

Prep Time25

Cook Time35

Decorating time20

Total Time1 20

Course: Dessert

Cuisine: American

Keyword: Halloween Cake, Halloween cake, Halloween Slime cake, Halloween mad science cake, Halloween Sprinkle Slime Cake

Servings: servings

Calories: 752kcal

Author: Sarah H

3 8 inch round cake pans
1 10 inch cardboard cake circle
Baker's floured cooking spray (optional, but I prefer this spray to parchment rounds)
Cake leveler
Cake turntable
large offset spatula
cake scraper or pastry cutter (to smooth frosting)
Squeeze bottle (or piping bag or a spoon - whatever you'd like to use to add the drip to your cake!)
6-inch (ish)/250mL Erlenmeyer flask (linked is the least expensive one I found online - it doesn't need to be able to withstand temperature fluxes; you're just using it to top the cake!)

2 white cake mixes
1 cup unsalted butter (or 2 sticks, melted & cooled - use instead of oil)
8 egg whites (no yolks-you can use egg whites from a carton to avoid wasting the yolks)
2 cups buttermilk (room temperature - use instead of water)
2 tablespoons clear vanilla extract
3-4 drops each teal, pink, and orange gel food coloring (I used Americolor gels, and chose colors based on my sprinkle mix - feel free to change out the colors, or even leave them out!)

8 ounces cream cheese (one package, softened)
1 cup butter (two sticks, softened)
5 ½ -6 cups powdered sugar
1 cup black cocoa powder (available on Amazon; this post explains why I love it so much!)
4-6 Tablespoons milk
1 Tablespoon vanilla extract
1/4 teaspoon salt if using unsalted butter
3-4 large drops black gel food color (use 5-6 large drops if using regular cocoa powder. I use black gel color pretty frequently, especially around Halloween, so I bought this large bottle from Americolor!)

6 ounces White Candy Melts I used Wilton Bright White
3 Tablespoons heavy whipping cream I used an incredibly thick Costco brand; you may need a bit less depending on the thickness of your cream
2-3 drops teal gel food coloring Add last; after candy melts are melted with whipping cream!
1 teaspoon Crisco / vegetable shortening (to coat the inside of the flask)
3-4 Tablespoons Sprinkle mix of your choice (I used ‘Freak Show’ by FancySprinkles but there are tons of other mixes like this one available online!)

Preheat oven to 350°F. Line three 8-inch cake pans with parchment rounds, or grease with non-stick or baker’s floured cooking spray.
Mix together all wet ingredients (butter, egg whites, buttermilk, vanilla) in a large bowl with a mixer or wire whisk. Blend in cake mixes for 30 seconds until moistened, then beat for 2 minutes until well combined.
Divide evenly into 3 bowls and color one pink, one orange, and one teal. Transfer batter to prepared cake pans.
Bake for 35-37 minutes (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. Cool completely before frosting. Set in the fridge or freezer to accelerate the cooling process if desired.

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, black gel color, and salt if needed and beat until well combined.

Once your cakes are cool, level them (if needed/desired). This can be done with a cake leveler or a large serrated knife and a ruler.
Place a smear of frosting on your cake circle (to keep the cake from sliding while you decorate it) and center your 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 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 an offset spatula and bench scraper for this part. Once your cake is covered, place it into the fridge or freezer to set the frosting. (This is a great time to make and color your ganache drip!)

Place heavy cream and candy melts in a microwave-safe bowl (don't add the color yet!) and microwave on 50% power in 30-second intervals until smooth, stirring in between. Once the mixture is completely melted and smooth, add in the gel color and mix until the color is even.
Once your ganache has cooled to a moderate temperature - it should be liquid but not hot so it doesn't melt your frosting - transfer it to a squeeze bottle or piping bag. You can use a spoon; it just won't give you quite as much control.
Slowly drizzle candy melt ganache around the upper edge of your cake, pausing every inch or so to let more fall in a drip down the side of the cake. Smooth any gaps or bumpy spots with a small offset spatula.
With a bit of paper towel and a skewer, chopstick, or straw (anything long/narrow enough to fit) spread crisco around to cover the inside of the flask. I added a Crisco layer, set the flask in the cooling oven for one minute to melt down a little bit, and then spread it again with the paper towel so it wouldn’t look white and hazy.
Shake a few teaspoons of sprinkles into the flask, and then shake the flask until the inside is covered. (Optional - you can also use a shortening-covered finger to add some sprinkles to your drips!) Place the flask on top of the cake, adding a few more sprinkles so they look like they're pouring out of the flask.
And you’re done! Cut in and enjoy!

(Please note nutrition information is an estimate, and may not be exactly accurate.)

Serving: 1slice | Calories: 752kcal | Carbohydrates: 98g | Protein: 9g | Fat: 38g