Preheat the oven to 325 degrees F (165 degrees C).

To make the crust: Beat softened cream cheese and 1/2 cup butter together in a large bowl. Stir in flour and mix to form a smooth dough.

Shape dough into 24 1-inch balls, then press into the bottoms and up the sides of ungreased mini muffin cups.

To make filling: Beat sugar, egg, 1 tablespoon butter, vanilla, and salt together until smooth; stir in walnuts. Spoon mixture into each crust.

Bake in the preheated oven until crust is golden and filling is set, about 25 minutes.