Creamy, zingy, and crisp, a classic Key lime pie is perfect for foodies who like their desserts to have a refreshing tartness. Making the custard-like filling is a simple job; mix egg yolks, condensed milk, sugar, and plenty of lime juice before pouring it into a crust and baking. However, there's one we can't recommend because it failed on all fronts in our taste test: Walmart's Marketside key lime pie. The lowest rated in our ranking of store-bought key lime pies, every layer of this confection was problematic. Second, the filling itself had an artificial character and an unusual aftertaste even though there aren't any artificial flavorings mentioned in the ingredients list.