Heat large nonstick skillet over medium-high heat. Add beef, onion, potato, carrot, parsnip and rosemary; cook stirring, breaking up beef with spoon, until beef is browned, about 8 minutes.

In medium bowl, whisk together broth, tomato paste, Worcestershire sauce, mustard, salt and pepper; stir into skillet and bring to boil. Reduce heat to medium-low, cover and simmer until vegetables are tender and mixture thickens, about 15 minutes. Mash mixture roughly with fork. Transfer to bowl; refrigerate to cool completely.

In small bowl, whisk egg with 2 tsp (10 mL) of water; set aside. On lightly floured surface, using 5-1/2-inch (14 cm) bowl, cut out 4 circles from each crust, rerolling scraps. Roll each circle into a 6-inch (15 cm) circle. Equally divide beef mixture onto one half of each circle, leaving a 1/2-inch (1 cm) edge. Brush edge with egg wash; fold dough over filling to enclose. Seal with fork. Cut slits on top; brush with egg wash. Sprinkle with coarse salt, if using. Place on large parchment paperlined baking sheet. Bake in 400°F (200°C) oven until golden brown, 15 to 20 minutes. Cool on wire rack for 5 minutes before serving.

TIP:

Freeze unbaked pies on baking sheet until firm. Transfer to freezer container; freeze up to 2 months. Bake from frozen, increasing baking time to 30 minutes or until golden.