Each year on March 14, math afficionados around the world celebrate the mathematical constant known as pi, which is represented by the Greek letter “pi.” Pi relates to the ratio of the circumference of a circle to its diameter, which comes to approximately 3.14159, but goes on infinitely. The celebration date is significant because it corresponds to the first three digits of pi, or 3.14.

While discussions about math and ponderings on pi in particular can fill the day, this calendar event also marks the opportunity to dig into pi’s homonym ... pie. Calculating circumferences and diameters may be even more intriguing when using an actual pie. Any pie can fit the bill, but why not feast on this recipe for “Rhubarb Hand Pies” from “Simply Scratch” (Avery) by Laurie McNamara?

Rhubarb Hand Pies

Makes 6 pies

3/4 pound fresh rhubarb, trimmed and cut into 1/2-inch pieces

1/3 cup packed dark brown sugar

1 teaspoon lemon zest

1 teaspoon fresh lemon juice

1/4 teaspoon ground ginger

1/4 teaspoon kosher salt

1 teaspoon pure vanilla extract

1 pie crust (2 discs), homemade (see below) or store-bought

1 large egg, beaten

Combine the rhubarb, brown sugar, lemon zest and juice, ginger, salt, and 1/4 cup water in a medium saucepan. Bring to a boil over high heat, then reduce the heat to medium-low and simmer for 12 to 15 minutes, or until the rhubarb mixture is thick. Remove from the heat, stir in the vanilla, then pour into a heat-safe bowl to cool completely.

Preheat the oven to 400 F. In a small bowl, combine the beaten egg with 1 tablespoon water to make an egg wash.

Roll out one disc of dough to 1/8 inch thick. Use a 6-inch biscuit cutter to stamp out 3 circles. Brush the outer edges with a little egg wash before spooning 2 tablespoons of the cooled rhubarb mixture onto one half of each circle. Fold the unfilled side over the filling and crimp the edges with a fork. Brush the tops of each pie with more of the egg wash. With a sharp knife, make slits in the center for ventilation and sprinkle each pie with 1/2 teaspoon of turbinado sugar. Refrigerate. Repeat with the second disc of pie dough and remaining filling.

Bake for 15 to 18 minutes or until the crust is golden and the filling bubbling. Let the pies cool on the baking sheet for 10 minutes before transferring them to a wire rack.

All-Purpose Pie Crust

Makes two 9-inch pie crusts

2 1/4 cups unbleached all-purpose flour

1 teaspoon kosher salt

1 cup ice-cold unsalted butter, cut into pieces

6 to 8 tablespoons ice water

In the bowl of a food processor, combine the flour, salt and butter and pulse until the pieces of butter are the size of peas and the mixture is crumbly; do not overmix.

Add the ice water 1 tablespoon at a time, pulsing after each addition, until the dough comes together in large clumps and resembles coarse, wet sand. Divide the dough in half, form into round discs, and wrap in plastic wrap. Refrigerate for 30 minutes.