We made 2 key lime slab pies at Family Beach Week this year at the Outer Banks for a crowd of 28 (not all of whom ate dessert) and we had most of one left over. This is a good way to make a tasty dessert for a large group. It is easy except for the labor required to get a cup of key lime juice per slab pie, which was time consuming since key limes are very small. This version is based on a recipe at www.southerneatsandgoodies.com. It is best baked in a high walled 10 x 15 inch jelly roll pan, although we did not have any spillage when we baked it in a lower walled cookie sheet.
For the crust
3.5 cups graham cracker crumbs (about 25 whole graham crackers)
14 Tbs. butter, melted (1-3/4 sticks)
¼ cup brown sugar
¼ cup white sugar
For the Key Lime Filling
3 cups sweetened condensed milk (2 12-oz. cans)
6 egg yolks
1 cup key lime juice
4 Tbs. grated key lime zest
For Serving
Whipped cream
Preheat the oven to 350 degrees. Spray a 10 x 15-inch pan with cooking spray.
In a large bowl, mix together the graham cracker crumbs, melted butter, brown sugar, and white sugar. Spread the crumb mixture over the surface of the prepared pan and press into an even layer. Bake for 10 minutes and then allow to cool completely.
While the crust is baking, mix together in a medium bowl the ingredients for the key lime filling. Pour the filling onto the cooled cracker crust and spread it evenly with a spatula or the back of a spoon. Bake for about 10 minutes, until small bubbles appear. Do not overbake. When done it will appear slightly jiggly.
Cool completely and store in the refrigerator. Divide into squares and serve with whipped cream.