The musical “Waitress” is about many things: love, friendship, independence and, of course, pie.

Broadway buffs who are also bakers would get a kick out of the forthcoming “Sugar, Butter, Flour: The Waitress Pie Cookbook” (out May 23, $25), which features recipes based on the show, from sweet ones, like The I Wanna Play Doctor with my Gynecologist Chocolate Mousse Pie to savory ones like The Betrayed by my Eggs Pie.

Perfect for the spring and summer is The Key (Lime) to Happiness Pie, described as a “margarita on a fork” thanks to the use of tequila and triple sec.

The Key (Lime) to Happiness Pie

Makes one 9 1⁄2-inch pie

Pretzel crumb pie shell

1 3⁄4 cups pretzel crumbs

2 tbsp. granulated sugar

6 tbsp. (3⁄4 stick) unsalted butter, melted

Filling

2 (14-oz.) cans sweetened condensed milk

4 large egg yolks

3⁄4 cup bottled key lime juice, preferably Nellie and Joe’s brand

1⁄4 cup blanco tequila

1 tbsp. triple sec

Salted whipped cream topping

1 cup heavy cream, chilled

2 tbsp. confectioners’ sugar

1 tsp. pure vanilla extract

1 1⁄2 tsp. coarse or flaked sea salt

Grated lemon zest

1. For the pie shell: Preheat the oven to 350 degrees. Toss together the crumbs and butter in a medium bowl to moisten. Press the mixture onto the bottom and up the sides of a 9 1⁄2-inch deep-dish pie pan. Refrigerate for at least 15 minutes to firm up the butter. Bake in the center of the oven for about 10 minutes or until just set and fragrant. Place on a wire rack to cool to room temperature.

2. For the filling: Whisk together the condensed milk and egg yolks in large bowl until smooth. Add the key lime juice, tequila, and triple sec and whisk until smooth. Let stand for 5 minutes to thicken. Pour into the pie shell.

3. Bake in the center of the oven for 15 minutes. Place on a wire rack to cool to room temperature. Refrigerate for 1 hour or until chilled.

4. For the topping: Use a mixer to beat the cream, confectioners’ sugar, and vanilla to firm peaks on high speed. Transfer the cream to a piping bag fitted with a rippled tip (#885) and pipe onto the pie decoratively. (You can also just pile the cream directly onto the pie and spread with an offset spatula if you prefer.) Sprinkle with the salt and lemon zest before serving.