Thursday, March 14, 2013

Pi Cake for Pi Day, 3/14!

Celebrate Pi Day by making a Pi cake for your Math Geek.  What is a "Pi" Cake you might ask?  "Pi" is the mathematical constant for the ratio of the circumference of a circle to its diameter, the ratio itself: 3.141592+.  It has been represented by the Greek letter "π".  I made this "Pi" cake for Cherise, my daughter-in-law, who was an engineering major in college, and loves all things "Pi". When I was looking on the web for all things, "Pi, I saw that someone had made a "Pi" shaped cake, so I had to make this for her.  Pi Day is celebrated on 3/14.

  I used a knock off recipe for Portillos chocolate cake. I needed  a firm cake to cut out the design, and  Portillos chocolate cake recipe is firm.  I knew that because I used to work at Portillos in the Catering Dept. and have eaten a lot of Portillos Chocolate cake over the years.  I baked two 9x9 cake layers, doubling the knock off recipe, and put chocolate frosting between the layers., Then, Scott cut out the design free hand, without a template, that's his "artist's eye". Unbelievable!!! He did a wonderful job!!. I couldn't have made the cake without his help.  That's why we make such a great team. After the design was cut out, I frosted the cake with Vanilla Butter Cream frosting, so the design would stand out.

Portillos Chocolate Cake
  • 1 box Betty Crocker Super Moist Chocolate Butter Recipe Cake Mix
  • 3 eggs
  • 1 cup ice cold water
  • 1 cup Hellman’s Mayonaise
  1. Preheat oven to 350 degrees and  Spray and flour desired pans.  I used two 9X9 pans, so I doubled the recipe, and had leftovers for cupcakes
  2. Combine cake mix, eggs, water, and mayonnaise in a large bowl. Beat on medium-high speed for 4 minutes until fluffy.
  3. Pour into prepared pans
  4. Follow baking instructions on box for your choice of pan.
  5.  Test for doneness
  6. Cool in pans 10 min.  remove to rack to cool

Cook's Note:

I used two recipes of the Portillos Chocolate Cake to make the "Pi" Cake. Because I didn't know how much batter it would take to fill a 9X 9 pan, I made each box, one at a time.  I filled one 9 x9 pan, and then used the remaining batter for cupcakes, then I repeated the process for the second 9X9 pan.

Vanilla Butter Cream Frosting
1/2 c butter, room temperature
2c. powdered sugar
1 tsp vanilla extract
1/4 c more or less milk, or half and half I used almond milk
Cream butter with an electric mixer, until light and fluffy.  Gradually add in powdered sugar and vanilla, and mix well, Add milk until desired consistency.
Frost top of the Pi  cake.


  1. Yayyy Pi day! This cake looks super yummy!

    1. Kayle,
      This cake is so good, moist and chocolaty.

  2. What a fun way to celebrate pi day! I love that you made a cake and not the normal pie (although those are equally yummy) This looks too delicious and too cute!

    1. Monet, Pie is good, but the cake is in the shape of the Pi sign, sp perfect for 3/14.

  3. I loved this idea. Wish Cherise Happy Birthday for me please. Hope you guys are starting to warm up even if it's a little.

    1. Gina,
      I thought that the Pi cake is fitting for Pi day, and it tastes so good!

  4. as Love this! It's great for Pi day. I heard on WGN this morning they were interviewing the owner of Sweetie Pie's in Skokie. It sounds like a fantastic bakery. Have you been there? Bet your DIL loved her Pi cake!

  5. Pam,
    I haven't been to that particular bakery. I don't get up North very often, but I'm sure they have wonderful pies. Cherise was surprised, but she loved her cake.


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