01 - Preheat oven to 325°F. Grease a 9-inch springform pan and line base with parchment paper.
02 - Mix graham cracker crumbs, granulated sugar, salt, and melted butter in a bowl. Firmly press mixture into the base of the pan. Bake for 10 minutes. Let cool completely.
03 - Using an electric mixer, beat softened cream cheese in a large bowl until completely smooth. Add granulated sugar and vanilla extract, mixing until combined.
04 - Add eggs one at a time, beating just until incorporated after each addition.
05 - Fold in sour cream and all-purpose flour until batter is smooth and homogenous.
06 - Evenly divide batter between three bowls. Leave one bowl plain, tint one with red gel coloring, and the other with blue, achieving vivid hues.
07 - Alternate spoonfuls of each colored batter over the cooled crust in a patchwork design. Swirl gently with a skewer or knife to achieve a marbled pattern without overmixing.
08 - Bake for 50 to 60 minutes or until the center is set but still slightly jiggly. Turn off oven, crack door, and cool cheesecake inside for 1 hour.
09 - Remove from oven and refrigerate cheesecake for at least 3 hours before slicing.