Preheat your Yoder Smokers YS640s Pellet Grill to 325ºF, set up for indirect grilling.
Slather the pork belly in the Worcestershire sauce. Season all surfaces with Cattleman’s Grill California Tri-Tip Seasoning.
Roast the pork belly on the second shelf of the grill until the internal temperature of the belly reaches about 190ºF, about 2 hours cook time.
Cool the belly to room temperature then wrap in foil and place in the refrigerator until fully chilled (a couple of hours or overnight).
Set up the grill for cooking on the griddle. Remove the second shelf, remove the diffuser door (or entire diffuser). Place the Yoder Smokers Reversible Cast Iron Griddle directly over the fire box, and set the temperature at 425ºF.
Slice the chilled pork belly into very thin slices.
Melt a couple of tablespoons of the mangalista lard on the hot griddle. Place the sub rolls cut side down to toast. Remove from the griddle when golden brown.
Add the thin sliced pork to the griddle. Cook until crispy around the edges, then remove from griddle and place on paper towels to soak up excess fat.
Add onions, and jalapeños and cook in the fat left behind on the griddle. Toss and cook until softened and browned. Add mushrooms. Cook until softened. Mix all. Move to the front of the griddle.
Portion pork out on the griddle. Top with veggies. Top each portion with a slice of American and a slice of provolone. Add some water to the griddle. Cover with a pan. Steam until the cheese is melted. Scoop off the griddle and land on the toasted rolls, spread with Kozlik's Dijon Classique.
Slice sandwiches in half and serve.