Shamrock Shake Cake: A Piece of Cake #14

Uncle O'Grimacey would be thrilled.

My birthday is March 18, so naturally I was really, really into St. Patrick's Day as a small child. I want to be clear here: my family is not Irish. I just loved the color green, and spring, and well... my birthday. It didn’t hurt that my mother was very enthusiastic about holiday decor, in general. So immediately after Valentine’s Day, the crepe paper hearts and the cupid novelty lights were promptly replaced with shamrock window stickies, green twinkle lights, and small potted shamrocks from the grocery store. And as far as I was concerned, these were also Bill Clark Birthday Month Decorations. But the real harbinger of the blessed season was the arrival of the Shamrock Shake at McDonald’s. 

The Shamrock Shake is somewhat of a cult food item, only appearing at participating restaurants for about 5 weeks a year. FYI, the 2021 release date was February 15th, so the clock is already ticking. If you’ve never had the pleasure, the Shamrock Shake is a distinctly American vanilla-mint milkshake in a slightly-unsettling shade of green found nowhere else in God’s creation.

Marketing website Doz reports that the Shamrock Shake was invented in 1970, in Chicago. Originally, the shake got its verdant hue from the dyed waters of the Chicago River. (Not true, but wouldn’t it be fun if we got that rumor going?) At that time, the Shamrock Shake was a vanilla ice cream base mixed with lemon/lime sherbert. Some time during the 70s, it just became a green vanilla shake (undeniably, the shake’s flop era). And finally, in 1983, we saw the debut of a thoroughly modern Shamrock Shake: a mint ice cream base, spiked with milk and vanilla syrup. The vintage commercials are… unsettling at best. Watch at your own risk.

Much like the shake that inspired it, my Shamrock Shake Cake had a couple of versions before this one. It was originally a layer cake I made at MeMe’s, and then, in the form of a snack cake, it was the final special before we closed the dining room on March 15, 2020. And so, a year later, here we are. After the last of the customers left on the 15th, I plopped into a corner seat and ate a big slice of this cake. And this March I’ll eat another slice, but without a restaurant to sit in. Everything and nothing changes—I still love the color green, and spring, and well… cake.

Yes, this is the second cake in a row with food dye and sprinkles. Please file your complaints with A Piece of Cake’s customer service department. (That’s me. And due to COVID-related cutbacks, we are not able to handle any new cases at this time.) This is the epitome of a silly snack cake and I don’t care. It’s supposed to make you smile when you look at it. It makes me smile when I even think about it. It’s my classic yellow cake base and fluffy American buttercream, vanilla and mint extracts, and if you do it right, sprinkles. So here’s to a second year of pandemic birthdays. God, let’s hope there isn't a third. 

Shamrock Shake Cake

For the Cake

1 ½ cup all-purpose flour

2 teaspoons baking powder

1 teaspoon salt

½ cup (1 stick) unsalted butter

1 ¼ cup granulated sugar

3 eggs

2 egg yolks

¼ cup canola oil

1 teaspoon peppermint extract

2 teaspoons vanilla extract

Scant ¼ teaspoon green gel food color (I used Chefmaster leaf green.)

¾ cup whole milk


1 cup (2 sticks) unsalted butter, room temp

2 cups confectioners’ sugar

1 teaspoon salt

½ teaspoon peppermint extract

1 teaspoon vanilla extract

Green gel food color

Make the Cake

  1. In a medium bowl, whisk together flour, baking powder, and salt. Set aside.

  2. In a stand mixer, with the paddle attachment, beat the butter and sugar until pale and fluffy.

  3. Add eggs and yolks, one at a time, beating until fully incorporated. 

  4. With the mixer running on medium, stream in the oil. Beat until fully incorporated.

  5. Add the extracts and food color. Beat until combined. Scrape the sides and bottoms, and beat until fully incorporated.

  6. Add half the flour mixture and mix on low. Add the milk, mix, and add the remaining flour mixture. Mix until fully combined.

  7. Spray and line a 9x9 square cake pan. Scrape in the batter and level.

  8. Bake at 350 degrees for 25-30 minutes. The cake is done when a toothpick comes out clean.

  9. Cool completely in the pan on a wire rack.

Make the buttercream

  1. Beat the butter until pale and light. Add confectioners’ sugar and salt. Mix on low until combined.

  2. Beat the butter and sugar on medium-high until very pale and fluffy.

  3. Add the extracts and a few flecks of food color. Beat to combine. Add more color if desired.

  4. Spread on top of the cool cake. The cake will keep longer if left in the pan. But it’ll be fancier if you turn it out onto a serving platter. For even more fancy, add some sprinkles. 

Quick Bites:

A Piece of Cake is written by Bill Clark and edited by Andrew Spena. Photography by Hunter Abrams. Logo design by Brett LaBauve.