Preheat your oven to 325°F (163°C).

In a mixing bowl, combine graham cracker crumbs and granulated sugar. Stir in melted butter until the mixture resembles wet sand, then press into the bottom of a muffin tin. Bake for 5 minutes and let cool.

Blend fresh raspberries and a bit of sugar in a food processor. Strain through a fine mesh sieve to create raspberry sauce.

In a bowl, whisk together granulated sugar and all-purpose flour. Gradually add softened cream cheese and lemon zest until smooth. Incorporate eggs one at a time, then fold in vanilla and sour cream.

Pour cheesecake filling over cooled crusts in muffin tin, filling each cup about three-quarters full. Add dollops of raspberry sauce and swirl with a toothpick.

Bake for 22-25 minutes until cheesecakes are puffed and nearly set. Cool in the pan for 10 minutes.

Transfer cheesecakes to a wire rack to cool completely. Refrigerate for at least 3 hours before serving.