Preheat the oven to 350°F. Line a 9×9″ pan with non-stick foil. Then evenly press the cookie dough into the pan. Bake for 15-20 minutes, or until a tooth pick comes clean. Allow to cool. You can place in the freezer for 15 minutes to help it cool faster.
For the cream cheese filling, add the heavy cream in a mixing bowl and beat for 2 to 3 minutes, or until a whisk forms. Then beat in the cream cheese and mix until smooth. Next add the sugar, powdered sugar and vanilla. Beat until smooth and creamy. Then spread over the top of the sugar cookie. Place in the freezer for 15 minutes.
For the blackberry filling, combine the blackberries, sugar and water in a small saucepan over medium heat. Cook for 5 to 7 minutes, stirring occasionally. Break down the blackberries with the back of your spoon.
Next, add spoonfuls of the blackberry filling on top the cheesecake filling. Then swirl using a knife to get the marble effect. Place in the freezer for at least 2 hours before cutting.
Once cut into bars, you can add a fresh blackberry on top if you'd like. Store in the refrigerator.