Rugelach

Combine the butter and flour in the bowl of a food processor and process until the chunks of butter are broken up and the mixture has taken on the consistency of wet sand, about 30 seconds. Transfer the butter-flour mixture to a large mixing bowl and add the salt, cream cheese, and sour cream. Mix the ingredients together vigorously with your hands, breaking up the cream cheese and working it into the f lour with your fingers until the mixture is crumbly and only pea-size chunks of the cream cheese remain. Turn out the dough onto a sheet of aluminum foil, press it down slightly into a thick disk, and wrap it very tightly in the foil. Refrigerate it for at least 20 minutes or overnight. Meanwhile, make the filling.