Preheat oven to 325°F (160°C). Line a 9×9-inch baking pan with parchment paper or grease lightly.

In a bowl, mix graham cracker crumbs, ¼ cup sugar, and melted butter. Stir until combined. Press evenly into the bottom of the pan.

Bake crust for 10 minutes, then remove and cool slightly.

In a large bowl, beat cream cheese until smooth. Add remaining ¼ cup sugar, sour cream, orange zest, and orange juice. Mix gently until well combined.

Add eggs one at a time, mixing slowly after each addition. Avoid overmixing.

Pour filling over crust and spread evenly. Bake for 30–35 minutes until edges are set but center is slightly jiggly.

Remove from oven and cool completely at room temperature. Refrigerate at least 4 hours or overnight.

Lift from pan using parchment paper, slice into bars, and serve chilled.