Preheat oven to 375°F.
Mix flour, salt, and granulated sugar.
Cut cold butter into flour mixture.
Beat egg with milk and vanilla.
Add wet ingredients to dry mixture.
Form dough into smooth ball.
Roll dough into large rectangle.
Combine cinnamon with brown sugar.
Sprinkle cinnamon mixture over half dough.
Fold dough over cinnamon filling.
Cut into twelve equal strips.
Twist each strip three times.
Place twists on parchment-lined baking sheet.
Brush tops with beaten egg.
Bake for 18-20 minutes until golden.