In a mixing bowl, combine the 1 1/2 cups graham cracker crumbs s and melted 1/4 cup unsalted butter. Mix until the crumbs are evenly coated with butter.
Line the bottom of a square or rectangular baking pan that fits your air fryer basket with parchment paper, leaving some overhang on two sides.
Transfer the graham cracker mixture into the lined pan. Use the back of a spoon or a flat-bottomed glass to press it firmly and evenly into the bottom of the pan. Place the pan in the freezer while you prepare the cheesecake filling.
In a separate mixing bowl, beat the softened 16 ounces cream cheese until it becomes smooth and creamy. Add the 1/2 cup granulated sugar and 1 teaspoon vanilla extract, and continue to beat until well combined. Finally, add 1 large egg and mix until the batter is smooth.
Pour the cream cheese mixture over the chilled graham cracker crust in the pan. Dollop spoonfuls of strawberry preserves on top of the cheesecake layer. Use a knife or a toothpick to swirl the 1/2 cup strawberry preserves into the cheesecake batter, creating a marbled effect.
Preheat your air fryer to 320°F (160°C), for 3-5 minutes.
Place the pan with the cheesecake mixture in the preheated air fryer basket. Set cook time for 20-25 minutes, or until the edges are set, and the center is slightly jiggly.
Remove the cheesecake bars from the air fryer and let them cool in the pan for about 15 minutes. Then, transfer the pan to the refrigerator and chill for at least 2 hours, or until the cheesecake is fully set.
Use the parchment paper overhang to lift the cheesecake out of the pan. Cut it into bars or squares. Garnish each bar with fresh 1/2 cup strawberries slices.