I use this one but I don't know the source sorry.
Plain Biscuits 180 grams
Butter 100 grams
Sweetened Condensed Milk 400 grams
Freshly Squeezed Lemon juice ½ Cup
Vanilla Essence/Extract 2 tsp
Cream Cheese 250 grams
BASE
Put the chopped biscuits and softened butter in a food processor to make a fine powder
Add in 1 tsp of vanilla essence/extract and process until blended in
Press into a prebuttered 20 cm tin
Chill in refrigerator for while you make the filling
FILLING
Sweetened Condensed Milk
Freshly Squeezed Lemon juice
Vanilla Essence/Extract - 1 tsp or to taste.
Cream Cheese
Blend the above well in a food processor, until well blended and mixture is smooth - should thicken up and be a bit stiff........
Pour into base and evenly spread with spatula
Refrigerate for at least 10 hours, so make evening before