Mix cracker crumbs, powdered sugar, and butter together.

Press mixture onto the bottom and slightly up the sides of a greased 9" springform pan.

Place springform pan in the middle of a sheet of aluminum foil and fold up the sides and place on a jelly roll pan (this will prevent anything spilling into your oven).

In mixer on low speed, beat cream cheese until soft.

Gradually mix in sugar until light and fluffy.

Beat in egg yolks, one at a time.

Mix in sour cream, flour, vanilla, lemon rind, and lemon juice until smooth.

In a separate bowl, beat egg whites until stiff peaks.

Fold egg whites into cheese mixture.

Pour in prepared pan.

Bake at 350 degrees F for one hour and 15 minutes.

Turn oven off and leave cake in for one hour.

Remove and let cool on wire rack.

Refrigerate overnight.