The base of our TARDIS cake used Crisped Rice Treats (aka Rice Krispy Treats). We needed something sturdy, and luckily Smitten Kitchen had the answer.

It’s all about the base

This week I’m wrapping up how I made the TARDIS cake for my new son-in-law. In Part 1 I told you about the Chocolate Buttercream Frosting my younger daughter & I used for the Chocolate Chip Cookie Cake layers, and Part 2 was the recipe for the Chocolate Chip Cookie Cake itself. Since the Chocolate Chip Cooke Cake was the upper 6-inches of the TARDIS cake, this week (with apologies to Meghan Trainor) it’s all about the base…the Crisped Rice Treats we used for the lower 12-inches of the tower.

If you watch those baking competition shows about fancy cakes, you’ll discover that Rice Krispy Treats are frequently used for structure. They’re cheaper and easier to make than cake layers, plus they’re easy to carve. Since our base needed to be sturdy, I went looking for a recipe that was, shall we say, firm…no soft and chewy treats need apply. I found what I needed in the Smitten Kitchen’s Caramelized Brown Butter Rice Krispies Treats , ironically a recipe that Deb considered a failure…she wanted a treat that was soft and chewy with a fuller brown butter flavor, but this recipe produced a treat that was too hard. Maybe not the texture Deb was looking for, but it was perfect for my needs. I didn’t bother with brown butter…I was after sturdiness, not taste.

Side note: Deb updated her recipe to make it softer while retaining the brown butter flavor she was after, calling them Salted Brown Butter Crispy Treats…you can find that recipe here.

Another side note: In case you’re wondering, the reason why I’m not calling this recipe “Rice Krispies Treats” is very simple…I would rather use a more generic name than something that’s copyrighted. Plus, since these treats are firm, I wanted to differentiate to avoid confusion. You’re welcome.

A third side note (I promise to stop after this): In order to make our 12-inch base, we made 6 batches of the Crisped Rice Treats recipe, and had a bit left over to make the pyramid-shaped top. Each batch was pressed into the same 9-inch square cake pan I used for the Chocolate Chip Cookie Cake. We were up to our elbows, ears, and other various body parts, in cereal and marshmallows!


crisped rice treats, TARDIS cake, groom’s cake, Dr. Who, Rice Krispy Treats, Smitten Kitchen
All the Crisped Rice Treats layers, the top, and the stacked Chocolate Chip Cookie Cake layers


TARDIS Cake Crisped Rice Treats

Adapted from Smitten Kitchen
Course: Dessert
Cuisine: American
Keyword: Marshmallows, Rice Krispy Treats, Smitten Kitchen
Servings: 16 2-inch square


  • 8 ounces butter, salted or unsalted
  • 1/8 tsp salt (if using unsalted butter)
  • 1 bag marshmallows (10 1/2 oz)
  • 1 box Crisped Rice cereal (12 oz)


  • Line 9-inch square cake pan with parchment paper or wax paper, allowing paper to overhang the sides (eases removal from the pan)
  • In a large pot, melt butter over medium-low heat.
  • When butter is melted, stir in marshmallows. Stir in 1/8 teaspoon salt( if using unsalted butter). Melt and cook, stirring often, until mixture turns pale brown, then stir constantly until lightly browned but not dark, 3 to 5 minutes.
  • Turn off heat, add cereal, and mix well, preferably with a silicone spoon or a spatula. Scrape into prepared pan and press down firmly. If necessary, butter hands to press mixture flat or use a small piece of plastic wrap.
  • Let cool, then remove from pan. If not using as part of a cake, cut into squares or bars as desired.

Assembly time!

The Crisped Rice Treats actually tasted great, and they did their job. My younger daughter did a fantastic on constructing and decorating this cake, complete with a little light at the top…our 18-inch high TARDIS cake was a huge hit with the groom (and the guests).

Here’s how the whole cake came together…

Straightening the sides

Because the cake pan was sloped, we had to trim the sides to even them out. The trimmings were delicious!


crisped rice treats, TARDIS cake, groom’s cake, Dr. Who, Rice Krispy Treats, Smitten Kitchen
Watch out…she has the electric knife!
Creating the tower

My daughter’s boyfriend helped her assemble the two parts of the tower, then she had to trim the Chocolate Chip Cookie layers to match the base. Again…delicious trimmings!


crisped rice treats, TARDIS cake, groom’s cake, Dr. Who, Rice Krispy Treats, Smitten Kitchen
Combining the base and cake layers, then make them even…in other words, more use of power tools!
Cover up!

My daughter added a light coating of frosting (called a crumb coat) to the tower. This helped the rolled-out blue fondant stick to the sides of the tower.


crisped rice treats, TARDIS cake, groom’s cake, Dr. Who, Rice Krispy Treats, Smitten Kitchen
A crumb coat of frosting helped the fondant stick to the tower
A TARDIS is born

The final step was adding the decorating details to make a nondescript tower turn into the TARDIS. We used white edible paper and edible markers for the fine work.


crisped rice treats, TARDIS cake, groom’s cake, Dr. Who, Rice Krispy Treats, Smitten Kitchen
From a blue tower to a TARDIS (I love the little light at the top!_
Giving the gift

We were so happy to give the groom his special cake…the surprise and delight on his face was exactly the reaction we were hoping for. His joy was evident as he, his brother, and one of his groomsmen showed their fandom as they posed with the cake (and a sonic screwdriver…don’t ask).


crisped rice treats, TARDIS cake, groom’s cake, Dr. Who, Rice Krispy Treats, Smitten Kitchen
The look on his face!


I hope you’ve enjoyed peeking into what my younger daughter and I did to make my older daughter’s wedding day special. I’ve always said that Food = Love, and preparing the DIY Wedding Cake and this TARDIS cake was one of the best ways to show how much we loved her and her new groom. That’s how this baking mama & baby do it.

Slainté! L’chaim! Cheers!


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