Process the butter, cream cheese, and cream in a food processor, electric mixer, or by hand to thoroughly combine.
Add the flour and salt. Process just until combined and the dough holds together in a ball. Turn the dough out onto a well-floured surface. Divide into 2 pieces. Flatten into disks and wrap each in plastic wrap. Refrigerate for at least 30 minutes before rolling out. If the dough is chilled overnight, take it out 15 minutes before rolling out.
Rub flour all over a rolling pin. Working with one dough disk at a time, place the disk on a clean, well-floured surface. Applying some pressure with the rolling pin, roll gently from the center of the dough to the top and bottom edges. Rotate the disk and roll to the top and bottom edges again. Reflour the work surface and rolling pin, turn the dough over, and continue to roll the dough from the center out to the edges. Turn over and roll again, rotating the disk to ensure even rolling until the dough is about 12 inches in diameter, thin but not transparent.