Steps
1. Preheat oven to 160°C (320°F).
2. Mix crushed graham crackers with melted butter and press into the bottom of a small ramekin.
3. In a bowl, beat cream cheese until smooth.
4. Add sugar, vanilla extract, and egg yolk, mixing until fully combined.
5. Stir in sour cream gently.
6. Pour the mixture over the crust in the ramekin.
7. Bake for 20-25 minutes until the edges are set but the center is slightly jiggly.
8. Cool to room temperature, then refrigerate for at least 2 hours before serving.