In a food processor, combine Ritz crackers, graham crackers, unsalted butter, and brown sugar.
Pulse until well-combined, but not too fine!
Press crust evenly into parchment-lined 9x13” baking dish.
Bake crust for 15 minutes at 350°F. Remove from oven and let cool.
Gather cornstarch, cold water, lime juices, lime zest, Greek yogurt, and sweetened condensed milk. Whisk cornstarch and cold water together.****
Whisk all key lime filling ingredients together in a large mixing bowl until smooth.
Pour key lime filling on top of pre-baked crust.
Bake for another 15 minutes at 350°F. Remove from oven, allowing it to cool completely.
Pop it in the fridge for 30 minutes to an hour. Then, slice bars into squares and (optional) serve with a dollop of homemade whipped cream or Cool Whip! Enjoy.
*About one and a half “fresh stacks” of Ritz Crackers**One sheet of graham crackers equals 4 crackers per sheet.***Nellie and Joe’s key lime juice is my favorite option for this recipe, but regular lime juice works just fine and is more budget-friendly. Regular lime juice is a little sweeter than key lime juice, but I found including the extra 1-2 Tbsp of juice from the fresh lime helped give it a little more tartness!****Whisking the corn starch and cold water together before whisking all of the ingredients together is preferable to avoid lumps.