In a medium bowl, combine graham cracker crumbs, melted butter, and granulated sugar. Mix until it resembles wet sand. Press about 1.5 tablespoons of the mixture firmly into the bottom of 12 muffin tin liners. Freeze while you make the filling.

In a large bowl, beat the softened cream cheese until smooth. Add powdered sugar, sour cream, lemon juice, and vanilla, and beat until combined. In a separate chilled bowl, whip the cold heavy cream to stiff peaks. Gently fold the whipped cream into the cream cheese mixture.

Divide the filling evenly among the prepared crusts. Smooth the tops. Cover with plastic wrap and refrigerate for at least 6 hours, or overnight, until firm.

Once firm, remove the mini cheesecakes from the liners. Add your favorite toppings just before serving.