The main ingredient in apple pie is, quite obviously, apples. Typically, tart varieties like Granny Smith or a blend of sweet and tart apples are used to create a balanced flavor profile. The apples are usually peeled, cored, and sliced before being mixed with sugar, cinnamon, and sometimes nutmeg, before being placed in a pie crust. The filling is often thickened with flour or cornstarch to achieve the perfect texture when baked. Apple pie is a classic dessert in many cultures, particularly in the United States, where it's considered a symbol of home and comfort.