I’ve always heard that key limes are not widely available because they have thin, delicate skins which make them hard to store and ship. So I was surprised to find key limes at my supermarket. Well, I had to try them and the price was right ($1/pound). Key limes are smaller and have a thinner rind than the typical supermarket Persian lime. They are also higher in acidity.
I thought I would be using them to make key lime pie since that seemed like the thing to do with key limes. But being a big fan of lemon squares, I thought I would make key lime squares instead. When used in baking, key lime juice is often combined with sweetened condensed milk to cut some of the acidity, but I prefer the assertive, bright flavor of a citrus curd type of filling as opposed to a mellow creamy, milk-based one. The Moosewood Restaurant cookbook has a recipe that uses a pecan crust as opposed to the usual shortbread crust found paired with citrus squares or bars. The pecans and brown sugar in the crust seem to go very nicely with the zingy tartness of the key lime curd.
I wanted to dress up my key lime squares and make them seem more special. Martha Stewart adorns her key lime pie with candied key lime slices. Since key limes are small, a slice would fit nicely on top of the square. So I channeled my inner Martha and did some candying. I simmered thin slices of key limes in simple syrup for about 45 minutes until the pith was translucent. Then I set the slices on a rack to air dry overnight. Although they were pretty, I can’t say I liked the taste. I found it a tad too bitter but some friends liked them, especially with the tart key lime filling.
Key Lime Pecan Squares
1/2 cup pecans, finely chopped
4 tbsp (2 ounces) unsalted butter, melted
3/4 cup all-purpose flour
1/3 cup light brown sugar
3 extra large eggs
1 1/4 cup granulated sugar
2/3 cup freshly squeezed key lime juice
2 tsp key lime zest
1/3 cup all-purpose flour
Preheat oven to 325F. Butter an 8-inch square pan.
Make the crust first.
In a bowl, combine the pecans, melted butter, flour and brown sugar. Blend with fingers or a fork until mixture is well combined and crumbly. Press mixture evenly into the bottom of the prepared pan. Bake for 25 to 30 minutes until crust is golden brown.
Make the filling while crust is baking.
In a bowl, whisk together eggs and sugar. Whisk in the key lime juice and zest. Sift the flour over the mixture and whisk until smooth. (Sifting the flour helps decrease the lumps of flour in the mixture.)
Remove crust from the oven when baked. Pour the filling over the still hot crust. Return to oven and bake at same temperature (325F) for 20 minutes or until the filling is set. Cool in pan for 1 hour before cutting into 16 squares (2x2-inch).
Optional: Dust key limes squares with powdered sugar and top with candied key lime slice.