Lemon Icebox Pie Recipe for Pi Day

Photo by Heather M. Ross

Pi Day, which takes place every year on March 14, celebrates the mathematical constant, Pi, or 3.14…

Some of our favorite ways to celebrate include Pi memorization contests, talking about Pi, making crafts and, of course, eating pie! Beyond just enjoying a tasty dessert, making your own pie is a great opportunity to get creative, spend time with family and explore math through baking.

In honor of National Pi Day, here is the recipe for Great-Grandma Ruby Ross’ Lemon Icebox Pie.

A red whisk stirs a thick, white mixture.
Whisking in progress | Photo by Heather M. Ross

You’ll need

1 graham cracker crust

1 can sweetened condensed milk (14 ounces)

1 small container of Cool Whip

1 cup of bottled lemon juice

Pie tin

Mixing bowl and instrument

Optional: crushed graham crackers or cherry pie filling (see additional recipe below or use canned filling)


Step 1: Prepare
Get ready by washing your hands, setting out the tools of the trade and reading over the recipe from start to finish. Put your graham cracker crust in the freezer.

Step 2: Mix
Mix equal parts Cool Whip and condensed milk in your mixing bowl.
Stir until smooth.

Math tip: Explain what equal means. If you have 14 ounces of condensed milk, how much Cool Whip do you need? Stirring time is a great opportunity to explain clockwise and counterclockwise by demonstrating with your spoon.

Step 3: Taste
Use a small spoon to taste-test your mix. Too sour? Add more whip and milk.
Not sour enough? Squeeze in a little more lemon.

Photo by Heather M. Ross

Step 4: Pour
Pour the mix into the cooled graham cracker crust; then, place the pie in the freezer until firm. The amount of time it takes to set will depend on the chill of your freezer and the
quantities in your mix.

Cherry Topping Recipe

1 cup pitted fresh cherries
2 tablespoons sugar
1 tablespoon cornstarch
1 tablespoon lemon juice
1 teaspoon of honey
Mixing bowl and stirrer


Stir the ingredients together thoroughly in the mixing bowl. Once combined, cover the bowl and refrigerate until pie is ready. Pour cherry topping overtop. Sprinkle with crushed graham cracker.

Pie Math

While it might seem like Pi Day is the perfect time to teach your children about mathematical Pi, younger kids might not be ready for all that just yet. For kids in third or fourth grade and younger, it might be better to talk about fractions.

Photo by Heather M. Ross

When the pie is done and ready for eating, count the number of people who are going to eat the pie with your child. Write that number down.

Portion the pie into eight equal sections. Subtract one section for each person eating the pie. Ask your child how many pieces are left after everyone has one. Talk about the fraction of the pie your family ate.

If you have three people and altogether, they ate three pieces of pie, you’ll have five pieces left. That’s 5/8 of the pie. Is there enough pie left for everyone to have seconds? Test it out!


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