01 - Preheat oven to 325°F. Grease a 9-inch springform pan and line the base with parchment paper.
02 - Combine graham cracker crumbs, granulated sugar, salt, and melted butter in a bowl. Press mixture evenly and firmly into bottom of prepared pan. Bake for 10 minutes, then let cool completely.
03 - Beat softened cream cheese until smooth using an electric mixer. Add sugar and vanilla extract, mixing until fully blended.
04 - Add eggs one at a time, mixing just until incorporated after each addition. Blend in sour cream and all-purpose flour until the batter is smooth.
05 - Divide batter evenly among three separate bowls. Leave one portion plain, color the second with red gel food coloring, and the third with blue gel food coloring until desired intensity is reached.
06 - Spoon alternating colors of batter onto the cooled crust in patches. Use a skewer or knife to gently swirl the colors, forming a marbled pattern while avoiding overmixing.
07 - Bake for 50 to 60 minutes or until center is just set yet still slightly wobbly. Turn off oven and leave cheesecake in oven with door cracked open for 1 hour.
08 - Remove from oven and chill in the refrigerator for at least 3 hours before slicing and serving.