1. For the patty dough, blend the flour with the curry powder and salt until well combined. Add the butter, shortening and water. Blend by hand (or in a food processor using on-off pulses) until the dough is crumbly with pea-size pieces. Be careful not to over mix.
2. Shape the dough into a ball, wrap with plastic wrap and place in the fridge for 1 1/2 to 2 hours or until firm.

Beef Patty Filling

1. Heat the oil in a large skillet, set over medium-high heat. Add the onion and cook for 5 minutes or until tender but not browned. Add the ground beef and veal, curry powder, thyme, salt and pepper. Cook for 5 minutes or until meat is browned. Stir in the broth and breadcrumbs, and cook until the mixture resembles a thick paste. Let cool completely.
2. To assemble the patties, roll the dough out to 1/8 inch (3mm) thickness and cut into 3-inch (8cm) rounds.
3. Place an equal amount of the beef mixture in the center of each piece of dough. Brush beaten eggs yolk over half the exposed dough. Fold the dough over to enclose the filling and pinch the edges to seal the patties. Brush the tops with remaining eggs.
4. Fire up your charcoal grill and prep the grill for cooking over indirect heat. You need a medium temperature of around 325 F to grill the patties. For gas grills, preheat the grill to medium then turn off one burner to achieve indirect heat.
5. Place planks on the grill over indirect heat for 3 to 5 minutes or until dry.
6. Place the patties on the planks and set on the cooler part of the grill. Cook for 30 to 40 minutes or until golden brown.