The main ingredient in a traditional key lime pie is key limes, which are small, tart, and possess a distinct flavor. The pie typically consists of a creamy filling made from key lime juice, sweetened condensed milk, and egg yolks, all poured into a graham cracker crust. The use of key limes gives the pie its signature tangy taste, making it a favorite dessert, particularly in Florida where the fruit is commonly found. Topped with whipped cream, key lime pie is not only delicious but also a refreshing treat, especially in warm weather.