Step 1 β Prepare the Pan
Preheat the oven to 350Β°F (175Β°C).
Line an 8 x 8-inch square pan with two pieces of parchment paper, leaving overhang on the sides.
Step 2 β Make the Crust
In a large bowl, combine the graham cracker crumbs, sugar, and melted butter.
Mix until the crumbs are evenly moistened.
Press the mixture firmly into the bottom of the prepared pan.
Use the bottom of a measuring cup to compact the crust evenly.
Step 3 β Bake the Crust
Bake for 10 minutes.
Remove from the oven and let cool completely.
Make the Key Lime Filling
Step 4 β Beat the Cream Cheese
Add the softened cream cheese to a large bowl.
Beat with an electric mixer for about 3β5 minutes, until completely smooth and creamy.
Step 5 β Add the Condensed Milk
Add the sweetened condensed milk.
Mix until smooth.
Step 6 β Add the Lime
Add the key lime juice and zest from 2 of the limes.
Mix until fully incorporated.
Taste the filling.
If you prefer it sweeter, add up to another 7 ounces sweetened condensed milk.
Step 7 β Fill the Pan
Pour the filling over the cooled crust.