First and foremost, make sure to preheat your oven to 325 degrees Fahrenheit.
Then, take your 13x9-inch baking pan. And line it with aluminum foil. With that, ensure that the foil extends over the sides. After that, set it aside.
Next, combine the graham crumbs or crushed graham with butter. In addition to that, blend it with two tablespoons of sugar in a medium or large mixing bowl. With that, mix till well combined.
Using a flat-bottomed glass, press your crumb mixture into the bottom of your prepared 13x9-inch baking pan. Also, you can use the back of your spoon if you want.
Then, beat the cream cheese in a large mixing bowl. Then, add a cup of the remaining sugar and one teaspoon of vanilla. Afterward, make sure to beat using an electric mixer. Do not forget to beat until well combined.
After that, add a cup of sour cream to the mixture and mix well. Then, make sure to add your eggs one at a time. Remember to beat at low speed after each addition. Also, avoid overbeating the mixture. Afterward, set aside.
Next, take your 13x9 inch baking pan with the crust. And pour the cream mixture. Afterward, smoothen the cream mixture using the rubber spatula.
Then, bake your cheesecake inside the oven for about 40 minutes. Or bake it until the center of your cheesecake sets but still jiggly.
After that, combine the 1/4 cup of sugar or remaining sugar and the rest of the sour cream. Then, add the vanilla to a mixing bowl. With that, ensure to mix using an electric mixer and beat until well combined.
Afterward, pour and spread the mixture carefully over your cheesecake. Then, bake your cheesecake for another 10 minutes. After that, remove your cheesecake from the oven when it is ready. And place it in a cooling wire rack. With that, ensure to let your cheesecake cool completely.
Once your cheesecake completely cools, place it inside the refrigerator and ensure to refrigerate for 3 hours.
Afterward, lift your cheesecake from the pan using the foil handles that we made earlier. Then, cut your cheesecake into serving portions.
After that, top your cheesecake with blackberries that you tossed in sugar or light syrup. Finally, serve and enjoy!