Shred the Seriously Sharp cheddar cheese on a box grater (large grate). Shred the Alpine cheddar on fine grate. Unwrap the bacon cheddar sticks and cut into cubes.
Boil a large pot of water and cook the pasta according to directions– draining the pasta just before it is al-dente.
Rinse the pasta in cold water and set aside.
In a small frying pan, fry the bacon pieces until cooked through. Drain the lardons on a paper towel.
Pour off most of the bacon grease from the pan and add ½ a tablespoon of butter to the same pan. Cook the onions in that pan until golden brown and caramelized, about 15 minutes.
Set the onions aside and wipe the pan dry.
Toast the breadcrumbs in the same pan until just golden brown. Transfer to a bowl.
In a large saucepan, make the mac and cheese sauce.
Begin by melting the butter until it begins to brown.
Stir in the flour and cook, stirring constantly, until well combined.
Pour in the milk, whisking constantly, until the sauce is smooth and thickened.
Stir in the cream cheese and mix until it dissolves.
Stir in the shredded Seriously Sharp cheddar cheese and cook, stirring constantly, until the cheese melts.
Season with salt and pepper and remove from heat.
Butter a 9x13 baking dish (sides and bottom) and pour in ½ of the cooked noodles.
To the noodles, add ½ of the bacon pieces, the caramelized onions, the tomatoes (mostly drained) and the green peas.
Sprinkle with additional shredded cheese and the cubed up bacon cheese sticks.
Pour in half the cheese sauce and gently stir to combine.
Repeat with a second layer, using up all the ingredients.
In the bowl of toasted breadcrumbs, add the Garlic Junkie seasoning, finely shredded Alpine cheddar and the scallions. Mix to combine.
Top the assembled mac and cheese with the breadcrumb mixture, covering heavily.
Cover the top of the dish with aluminum foil and refrigerate until 1 hour before serving.
1 hour before serving, preheat your Traeger grill to 400*.
Place the covered dish in the grill and allow to cook for 20 minutes.
After 20 minutes, remove the alumninum foil and continue cooking for another 20 minutes.
Remove the pan from the Traeger when the dish is hot and bubbling.
Allow to sit for 5 minutes before serving.