In a shallow dish combine the sauce and seasoning and mix well.
Add the beef slices and turn to coat.
Cover and place in the refrigerator for 30 minutes.
Preheat your Traeger griddle to medium high heat.
Defrost the phyllo dough.
Chop the onion into small dice.
Shred the Vermont Sharp Cheddar Cheese on the finest setting of your box grater.
When the grill is hot, cook the steak until just done-- about 2 minutes per side.
Transfer the grilled steak to a plate and tent to cover.
Add the onions to the grill and cook in the beef fat until soft and translucent.
Remove from grill and set aside.
Preheat your Traeger grill to 375*.
On a piece of parchment, unroll the phyllo.
Using a rolling pin, carefully roll the dough into a large rectangle.
Cut the phyllo into 4 even rectangles. Roll each rectangle further as needed.
Chop the grilled NY strip slices into small dice.
In a bowl, combine the chopped steak, sautéed onions and shredded cheese.
Mix well to combine.
On the right half of each phyllo rectangle, pile a generous scoop of the meat/cheese mixture.
Pull the left side of the phyllo rectangle over the right (like a book) and cover the meat.
Use a fork to crimp the edges of each hand pie.
Brush the hand pies with beaten egg.
Then sprinkle each hand pie with a little more shredded cheese.
Bake the hand pies, on a cookie sheet, in the grill until golden brown and puffy-- about 20 minutes.
Transfer your steak and cheddar hand pies to a serving platter and enjoy warm.