Using an electric mixer on medium speed, beat the cream cheese and butter until creamy. Reduce mixer speed to low and gradually add the flour. Mix just until combined.
Shape the dough into 48 balls, using a scant tablespoon of dough at a time. Place the dough balls on a baking sheet. Cover and chill for 30 minutes.
To make the filling:
Preheat oven to 350°F (175°C). Lightly grease 48 mini muffin cups.
Place 1 dough ball into each cup. Press the dough into the bottom and up the sides of the cups, forming a pastry shell. If you have a tart tamper, this is a perfect use for it. Coat it lightly with a bit of flour to keep the dough from sticking to it.
Whisk together the eggs, sugar, buttermilk, lemon juice, and melted butter. Fill each pastry shell with the mixture.
Bake 18-22 minutes, or until the filling is set. Cool in pans on wire racks for 10 minutes. Then, carefully remove the tarts from the pans to cool completely on wire racks.
Notes
If you'd like, garnish these with with toasted coconut or toasted almonds.