For the Graham Crust. mix flour, brown sugar and salt. Cut in butter with a pastry cutter. When fine and crumbly press into a 9 x 12 glass pan. Cook approx 25-30 minutes until tan/brown at 350 degrees.
Let it cool, then crumble up and re-press into the pan. This is really fun to do with your hands, it's like playing in the sand!
Juice the lemon and limes. Should make at least 1/2 cup.
Cream together, cream cheese and sugar.
Add sour cream, lemon/lime juice, egg yolks, salt and vanilla.
In a separate bowl beat the eggs white until fluffy and fold in to the cream cheese mixture.
Pour into the pan with the graham crust and bake at 375 approx 45 minutes. Check for doneness with a toothpick.