Combine flour, sugar, and salt in a food processor.
Add butter, cream cheese, and egg yolk.
Process until the dough comes together in a crumbly mass.
Knead the dough on a floured surface until smooth.
Divide into 4 portions, shape each into a rectangle, and wrap in plastic wrap.
Refrigerate for at least 1 hour or up to 3 days.
Melt chocolate in the microwave or double boiler until smooth and mix in sugar and salt.
Remove one portion of dough from the refrigerator and roll into an 8x11-inch rectangle on a floured surface.
Spread 1/4 cup of chocolate filling evenly over the dough, leaving a 1/4-inch border.
Roll the dough tightly into a cylinder, starting from the long side.
Place seam-side down on a prepared baking sheet.
Repeat with remaining dough and filling.
Refrigerate rolled dough for 20-30 minutes.
Preheat oven to 375°F.
Slice off uneven ends of each roll and discard.
Slice rolls into 1-inch-wide pieces and bake for 18-20 minutes or until lightly golden.
Cool on a rack and enjoy fresh or store for up to 3 days or freeze for longer storage.