Preheat your oven to 325°F (160°C). Line a 9x13-inch baking pan with parchment paper, leaving an overhang on the sides.

In a medium bowl, combine the graham cracker crumbs, sweetener (if using), and melted butter or coconut oil. Press the mixture into the bottom of the prepared pan. Bake for 8-10 minutes, then let it cool slightly.

In a large mixing bowl, beat the softened cream cheese and granulated sweetener until smooth.

Beat in the eggs one at a time, then stir in Greek yogurt, vanilla extract, cocoa powder, apple cider vinegar, red food coloring, and sea salt until smooth.

Pour the cheesecake filling over the cooled crust, spreading it evenly.

In a small bowl, beat together the cream cheese, sweetener, milk, and vanilla extract until smooth.

Drop dollops of the cream cheese mixture over the red velvet filling, then swirl with a toothpick.

Bake for 30-35 minutes, until edges are set and the center is slightly jiggly.

Let it cool completely, then chill in the refrigerator for at least 4 hours or overnight.

Lift the cheesecake out of the pan using the parchment paper and slice into bars.