It's everything you love about a ham and cheese sandwich, but better!
Unfold pastry on work surface. In small bowl, whisk egg and mustard; brush half over pastry. Sprinkle with both cheeses and rosemary. Top with ham. Cut pastry into 8 strips. Twist each strip 3 times; arrange 1 inch apart on greased baking sheet. Brush with remaining egg mixture. Bake at 425° until golden, 16 to 18 minutes.