Using a food processor (or a plastic bag and a rolling pin), break up the biscuits until they are a medium to fine powder, bigger bits are ok too.
Add the sugar, salt and margarine and mix well.
Prepare a round springform or pie dish and press the crumb mixture into the base, pressing it slightly up the sides.
With a hand mixer, mix the cream cheese, eggs, sugar and vanilla until smooth.
Gently pour the mixture over the crumb base.
Bake in a 180C oven for 30 minutes.
Remove from oven and allow to cool before adding the berry topping.
While the cake is baking, add the berries, water, sugar and thickener to a pot on your stove.
Mix well and bring to a rapid boil.
Drop the temperature to a simmer and allow the berries to reduce by 1/3.
Allow the berries to cool before pouring over the top of the cooled cheese cake.
Recipe adapted from King Arthur Flour Easy Cheesecake