I had a couple of friends over for lunch and this is what one brought for dessert. Yum! She didn’t give me the recipe, but she told me how to make it.

A whole bunch of limes (she said about 20, so I’m sure they were key limes. She said they were small)
1 can sweetened condensed milk
whipping cream (a pint? I don’t think she said. And I think it was whipping cream, possibly heavy)
graham crackers
whipped cream

Juice the limes and add them to the milk and cream in a medium bowl. Mix thoroughly. Layer graham crackers and mixture in a 9×13 pan. Maybe 4 layers of each? Top with whipped cream and garnish with lime zest. Heaven.