Erupting Volcano Birthday Cake!

My son turned 6 on Friday. How on earth is that even possible?

Anyone that knows me well, knows that I have a thing for themed birthday parties…and that I try (in a somewhat obsessive way) to make cakes that go along with the theme. So, when I planned a science birthday party for my kiddo, I scratched my head for a while to think of a cake with a science theme…and, in a Eureka moment, realized that I just HAD to make an erupting volcano. In a seriously funny coincidence, when I started googling to figure out exactly how I was going to accomplish this ridiculous feat of cake, I came up with a post by my good friend Sheri Gurock about her own Erupting Volcano Cake experience from 5 years ago and discovered that we had even both hired Mad Science to entertain the kids–even though we are in different states!

The recipe/directions that follow are a combination of what Sheri did and my own. I used own favorite chocolate cake recipe from my mom, Gloria Kobrin’s, Kosher Cookbook recipe app.


Chocolate Cake Makes 2 10 inch round cakes, 1 16 inch round and 1 8 inch round, 1 bundt cake and 1 10 inch round

  • 1 ¾ cup flour
  • 2 cups sugar
  • ¾ cup unsweetened cocoa
  • 1 ½ teaspoons baking soda
  • 1 ½ teaspoons baking powder
  • 1 teaspoon salt
  • 2 eggs
  • 1 cup water-room temperature
  • ½ cup vegetable oil
  • 2 teaspoons vanilla
  • 1 cup boiling water
  • baking spray

1. Cut two 10” circles of waxed/parchment paper. Spray bottom of pans lightly and place one paper circle in each. Spray top of paper and sides of pan lightly.

2. Preheat oven to 350 degrees F.

3. Pour all dry ingredients into mixing bowl. Mix on slow speed for one minute. Make a well in the center and add water (room temperature), vanilla, eggs and oil. Mix on medium speed for two minutes. Change to slow speed and add boiling water. Beat for one minute, then take spatula and scrape batter down the sides into the bowl. Be sure to scrape spatula down to the very bottom of the mixing bowl so that all the batter is completely blended. Beat on medium speed one minute more.

4. Divide batter evenly between both cake pans.* Place pans in oven – one on the bottom and one on the middle shelf. After 15 minutes, reverse the pans and bake 10-15 minutes more. Layers should be coming away from the sides of the pans when done. Test with a toothpick or cake tester to be sure. Only some moist crumbs should adhere to the tester. Place finished layers on cake racks and cool 10 minutes; then invert racks over layers and gently shake them out. Carefully peel waxed paper from bottom of layers. Cool completely before icing. These layers may be wrapped and frozen for later use if desired.

Note: For this cake, I used 2 10 inch rounds one 16 inch round and a bundt cake so I made 3 times the recipe. I doubled it once and then made an additional extra batch of batter because had I tripled it, I would have never been able to mix it all together! I ended up with one extra 8 inch cake later in the freezer to use at another time.



Cookies & Cream Filling (makes about 6 cups)
From “The Whimsical Bakehouse”
2 1/2 cups heavy cream
1/4 cup confectioner’s sugar
1/2 tsp vanilla extract
20 chocolate sandwich cookies crushed into medium size pieces (I put them in a Ziploc bag and rolled over them with a rolling pin)

Beat the cream, sugar and vanilla in the bowl of an electric mixer at high speed until stiff. Gently fold in the cookies.

Lava Buttercream
Makes 2 1/3 cups, plenty if you’re just using it to level your layers, make lava and do some decorating.
1 stick of butter
1 box of confectioner’s sugar
1/4 cup of milk
1 tablespoon vanilla
1/4 tsp salt

*gel food coloring in orange, red and yellow*

Using the paddle attachment on your stand mixer, cream the butter at high speed until light and fluffy. Mix in the sugar alternating with the milk, beating well after each addition. Beat in the vanilla and salt, then add a bit more milk if needed to reach a good consistency for spreading.

Chocolate Frosting
Reserve half of this frosting to mix with crushed Oreo cookies if you want the “dirt” effect on your volcano. Makes about 3 cups. If you’re making a big cake, double it.

4 cups confectioners sugar
1 1/3 cups cocoa
1/4 tsp salt
1/2 cup milk, plus additional
1 tsp vanilla
4 tbsp butter

Whisk together the sugar, cocoa and salt. Add the milk and vanilla and beat with the paddle attachment of your stand mixer until blended and smooth. Beat in the butter and then add milk to reach your desired consistency.

Erupting Lava:

2 Tbsp Marshmallow Fluff

2 tsp warm water

a drop or two of red food coloring

additional hot water

Dry ice

Directions in step 7


1. Bake cakes and cool completely. If you ice a warm cake you will have a big mess on your hands. If it’s never happened to you, just trust me on this one.

2. Make Cookies & Cream Filling, Lava Buttercream and Chocolate Frosting.

3. Pipe a circle of Lava buttercream (not yet colored) around the outside of each cake layer, fill the center of the circle with Cookies & Cream filling and carefully pile up your layers. That extra circle of icing will both keep your filling from seeping out and also help ‘glue’ your layers together.

4. Carefully enlarge the hole of your top bundt cake so that it is large enough to insert a 6-8 ounce jam jar, vase or small glass. In my unfrosted picture, you can see the jar already inserted into the cake. I used a jar so that I could cover it to make the glass more secure for transport to the party. If you use a jar, don’t screw the cover on all the way or it will be too hard to get off without messing up all of your frosting. This is where your erupting lava will go.

5. Frost the entire cake pile with chocolate frosting. I frosted it once, thinned out a little bit of extra frosting with some water and mixed in some crushed cookie crumbs and lightly frosted it again. I also sprinkled some more cookie crumbs in random spots all over the cake so that it would look textured and ‘rocky’.

6. Lava Buttercream: Take 3 separate small microwavable bowls and put a little bit of your leftover buttercream icing in each one. Add a drop of gel food coloring to each–if you use liquid food coloring, use a really tiny amount or your consistency will be totally off–and mix well. You should have one bowl of red, one bowl of orange and one bowl of yellow icing. Zap each bowl for 10-15 seconds, until it reaches a thick liquid consistency and drip it over the top of your cake. Instead of making my own dinosaur out of fondant, which was my original intention, I bought a small dinosaur figurine and place him on the bottom of the cake.

7. For your eruption: Mix together 2 Tbsp Marshmallow Fluff, a drop or two of red food coloring and 2 tsp warm water until smooth. Right before serving, take off the top of the jar that is embedded inside your cake and carefully place in it a couple of good sized chunks of dry ice. Add the fluff mixture and pour in some hot water. The volcano will erupt with smoke and the lava will bubble over–you can really only see the smoke in my video clip, and my lava bubble up but not over onto the cake.





One thought on “Erupting Volcano Birthday Cake!

  1. Thanks for your visit from the Alexa Hop. This is pretty fun. I bet the kids loved it!! Hope you are having a great summer so far. Hope to see you again. PS. I love the photo of your son & grandma, it reminded me of trekking through the city with mine as a kid. Theresa @

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