Pi Day cake


Since I was a kid, I’ve always been a fan of celebrating Pi Day. I mean, I’ll take any excuse to eat pie even if there’s a little math in the mix (ok, I always loved math class). My high school went all out for Pi Day: everyone signed up to bring a different kind of pie to math class, and all of the math teachers had custom shirts made. I didn’t like much about high school, but I plan on taking this Pi Day energy with me wherever I go. Also, I once lived in unit 314 in an apartment complex and was planning THE most epic Pi Day party but unfortunately I lived there for less than a year, and that part of the year did not include March 14th. Not the best story, but the point is that I love Pi Day. Onto the baking!

I have not yet ventured into the pie baking world, but I love piping and had a vision for a Pi cake. I’m calling it a cake, but it’s actually a delicious blondie underneath. I used this recipe. Since my favorite part of this process is decorating, I’ve realized I don’t necessarily need to have a cake underneath. Plus, denser desserts are easier to decorate since they are sturdier and the crumbs don’t make their way into the frosting as easily. So, I went with a blondie.

I cut the recipe linked above in half and made it in an 8×8 pan. I also added some fun pink and blue chocolate chips and slivered almonds. Maybe you’re thinking “but the cake is a circle.” It is indeed. First, I made it in a square pan:

And then used my 6-inch cake pan as a guide to cut a circle out:

The biggest benefit here is that I got to taste the blondie scraps before decorating. I’m not entertaining these days, but if I was I suppose this would be a good way to make sure it tasted good (but yeah, I really just wanted to nom on some scraps). I’m also not sure if brownies bake as evenly in a circular pan, but now I’m curious.

Next I made a big batch of American buttercream. I kept about half of it white, and split the rest into three bowls and dyed them pink, blue, and teal. I didn’t think I was very good at color theory, but I must say these colors look pretty good together. I placed the frozen blondie circle on an 8-inch cake round and covered the top and sides in a layer of white frosting. Because the blondie is pretty dense and I frosted it frozen, I didn’t have to do a crumb coat. And while I can be a perfectionist about getting the top smooth, I’ve realized that once you’ve decorated it you can’t really see the strokes that are noticeable in this photo:

I put this in the freezer to set for about 5 minutes, and then it was time to make the Pi symbol! To do this (and any piping), I made a thin line in the Pi shape with a toothpick and then piped the frosting on with a Wilton 3 tip. This looked super messy at first, but I carefully smoothed it with a warm angled spatula. This may have been easier with fondant, but I don’t really like how it tastes and I love working with buttercream.

Time for the Pi digits! To make sure the numbers were the same height all the way around the cake I measured 3/4 inch from the edge, making very slight toothpick lines around the circumference. I then lightly wrote each number with a toothpick before I piped it. It was important that I only made my toothpick outline one number at a time – the actual piped numbers always took up more space than I anticipated. While doing this, I also discovered that my husband had way more digits of Pi memorized than I was expecting. I can’t really say I’m surprised, but I was impressed.

And tada! The cake / blondie / pi(e) was done. Time to photograph and slice:

I’m still learning a lot about food photography, but I’m always amazed how much props can help a photo! Sure enough, my husband had a TI calculator lying around in his office (as one does), and the piping bags + tape measure made great additions to this photo. It’s also worth noting that my first slice was 1/2 a radian!

Finally, nobody asked, but 3 is the hardest number to pipe. I know you were all wondering.

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