Easy Key Lime Pie Bars

Start With a Crumb Crust

Below you’ll find my basic graham cracker crust recipe. It fits into a 9-inch square baking pan perfectly, as well as many 8-inch and 10-inch pans, and pie dishes. I love this particular crust because it’s altogether crunchy, buttery, thick, and not overly sweet like many crumb crusts of its kind. I use it for strawberry cream cheese pie, lemon blueberry cheesecake bars, and these mini key lime pies.

• You need a careful ratio of 3 ingredients: graham cracker crumbs, sugar, & melted butter.
• Use a food processor or blender to grind 12 full-sheet graham crackers into crumbs.
• Stir the graham cracker crumbs and sugar together before mixing in the melted butter.
• Press into your lined pan just until it’s no longer crumbly. Do not pack down too hard.

Other crust options:

1. Gingersnap Crust: The original version of this recipe called for a crust made from finely crushed gingersnap cookie crumbs mixed with melted salted butter. I used store-bought gingersnaps, the hard and crunchy kind. The sweet/spicy flavor of the gingersnaps is an unexpected and delightful contrast to the tangy flavor of key lime. If you’d like to make the crust with gingersnaps, you can find the instructions in the recipe Notes. (Gingersnap cookie crumbs would be unbelievable on these upside down key lime pies, too!)
2. Graham Nut Crust: Or you could combine graham cracker crumbs with ground macadamia nuts, like I do in my favorite key lime pie recipe.
3. Pretzel Crust: Or try the pretzel crust from these peanut butter cup pretzel bars.

No matter which crumb crust you choose to use, press it into a 9-inch square baking pan lined with parchment paper, and give it a head start in the oven while you mix together your filling. (10 minutes prebake, as instructed below.)

Key Lime Pie Square Filling

This 4-ingredient filling is tart, creamy, and sweet. The perfect balance of all three. Tangy, not sour. Smooth, with just the right custard-meets-cheesecake texture.

First, you need key lime juice.

You also need the following ingredients:

1. Cream Cheese: I don’t use it in my key lime pie recipe, but I wanted today’s filling to lean a little more towards key lime cheesecake. The flavor is subtle—we’re only using 4 ounces of cream cheese in the filling (1/2 of a brick), and that small amount manages to produce the creamiest key lime pie bars in the world. Avoid the fat-free kind.
2. Egg Yolks: Egg yolks stabilize and set up the key lime filling.
3. Sweetened Condensed Milk: One 14-ounce can of full-fat sweetened condensed milk sweetens the dessert and provides a smooth texture. I also use this in my oatmeal lemon crumble bars.
4. Lime Zest: Lime zest gives the filling some colorful speckles, not to mention even more lime flavor. Zest either 1 regular lime or 2 key limes.

Spread the filling over the crust while the crust is still warm. Why? This will help the filling adhere to the crust a little better.

How to Cut Neat Squares

Cool baked key lime pie bars at room temperature for about 1 hour, and then refrigerate them for 2 hours or until the bottom of the pan feels cold. If you cut the bars into squares too early, they’ll fall apart. If I’m serving these at a party or event, I prepare them the night before just so I know they’ll cool and chill long enough to yield neat squares.

Slice them with a sharp knife and wipe the knife clean between each cut.