For the gravy:
1) Add butter and minced shallot to a medium pot over medium heat. Cook shallot until soft, 2-3 minutes. Season with a pinch of salt.
2) Stir in flour and cook for a minute until it starts to turn a light tan color.
3) Stir in beef stock slowly so it doesn’t clump. Stir until gravy is smooth and bring to a simmer to thicken. Add Worcestershire sauce, mustard, and season with salt and pepper. Turn heat to low and keep warm until needed.
Prepare grill for direct heat either by lighting charcoals and letting them burn down, then spreading them out, or heating gas grill over medium-high heat.
1) Split 1 pound of frozen large fries or wedges between two large pieces of foil. Drizzle each pack with 1 tablespoon melted butter. Fold the foil up around the fries to form some sides and cover each pack with another piece of foil. Seal the packs closed tightly.
2) Add packs to grill over direct heat, covered. Grill for 10 minutes, then flip and grill for another 10 minutes.
3) Flip packs back and carefully open them up to release steam (be careful). Take cover off of packets and sprinkle each one with cheese curds or cubed cheese. Cover grill and grill for another 5-7 minutes until cheese is just starting to melt.
4) Drizzle poutine packs with brown gravy and cover again for another few minutes.
5) Before serving, garnish packs with fresh chives!