Ingredients
1 cup graham cracker crumbs
3 tbsps sugar
3 tbsps butter melted
5 pkg (8 oz/ 226 gms each) philadelphia cream cheese softened
1 cup sugar
3 Tbsp flour
1 Tbsp vanilla
1 cup sour cream
4 eggs
1/3rd cup seedless strawberry jam

Method
1) Preheat oven to 325 ^o F/ 160 ^o C. Line 13 by 9 inch baking pan with foil extending over the sides of the pan. Mix cracker crumbs, 3 Tbsps sugar & the butter. Press firmly on bottom of the prepared pan. Bake 10 mins.
2) Beat cream cheese, 1 cup sugar, the flour & vanilla in a large bowl with electric mixer on medium speed until well blended. Add sour cream, mix well. Add eggs, one at a time mixing on low speed, after each addition until just blended. Pour over crust. Gently drop spoonfuls of jam over batter, cut through the batter several times for a marble effect.
3) Bake 40 mins or until the centre is almost set. (It took me 1 hr) Cool completely. Refrigerate at least four hours or overnight. Lift cheesecake from pan using foil handles. Cut into 16 pieces to serve. Refrigerate remaining cheesecake.

Source Philadelphia cream cheese recipe.

Note: My baking time at 160^o C/ 325^o F was 1 hour. Cheesecake is done when the centre is set & still a bit wobbly when shaken