Preheat your oven to 325°F (163°C). In a mixing bowl, combine graham cracker crumbs and sugar, then pour in melted salted butter. Stir until the mixture resembles wet sand. Divide this crumb mixture evenly into a greased muffin tin, pressing it down firmly with a spoon to form a compact crust. Bake for 5 minutes or until lightly golden, then set aside to cool.

In a blender or food processor, puree fresh raspberries with a tablespoon of sugar until smooth. To ensure the swirl is seedless, strain the mixture through a fine mesh sieve and set aside.

In a large mixing bowl, whisk together granulated sugar and all-purpose flour. Add softened cream cheese and lemon zest, beating with an electric mixer until smooth and creamy. Add eggs one at a time, incorporating each before adding the next. Mix in vanilla extract and sour cream.

Evenly pour the cheesecake filling into each muffin cup over the cooled crust. Dollop the prepared raspberry sauce atop the filling and gently swirl the mixture with a toothpick.

Bake the cheesecakes for 22-25 minutes, or until the centers are just set and slightly jiggle. Cool to room temperature.

Cover the muffin tin and chill in the refrigerator for at least 3 hours, ideally overnight. Carefully remove from the muffin tin and enjoy.