Assemble your ingredients.
If making the burgers and toppings at the same time, preheat your Traeger grill with a cast iron griddle inside. (Sauce and onions can be made ahead of time)
Thinly slice the sweet onion into ¼ inch discs and set aside. Using the scraps of the onion you didn’t slice, finely dice about 2 tbsp of sweet onion to use for the sauce.
In a saucepan, saute 1 tbsp of butter with the 2 tbsp of chopped onion until translucent and beginning to soften.
To the onion, stir in the brown sugar, mustard, worchestershire sauce, soy sauce, hot sauce and ketchup. Mix to combine and bring to a boil.
Pour in the Coca-Cola and bring the sauce back to a boil.
Allow to cook for about 15 minutes until reduced and sticky.
Remove from the heat and allow to cool to room temperature.
In a large shallow pan, melt the remaining butter and add the onion discs. Separate the pieces as necessary to spread onions evenly on the bottom of the pan.
Cook the onions over medium/high heat until beginning to brown, stirring occasionally.
After about 15 minutes of cooking, pour in the Coca-Cola and bring to a boil.
Let the onions keep cooking in the Coke until tender and the soda has reduced by at least half.
Remove from the heat and cover to keep warm.
While cooking the onions, make the burger blend.
In a bowl, combine the ground pork and ground beef and season liberally with the steak seasoning.
Using your hands (gloves recommended), combine the meat until uniform in texture.
Divide meat mixture into 8 balls– about the size of your fist.
When the grill and cast iron griddle is very hot, make the burgers.
Spray a light coating of cooking oil on the hot grate.
Working in batches place an even number of meat balls on the griddle, leaving ample space between balls.
Using a flat spatula and a piece of parchment paper, smash the meat balls a thinly as possible. Use a gloved hand to press on the spatula.
Cook the burgers on the first side for about 2 minutes, then flip over.
Top each burger with a slice of cheese and continue cooking for 1-2 minutes.
Toast the buns alongside the burgers.
Pull the burgers and the buns from the grill.
Assemble your tailgating burgers by placing two burger patties on a bun, topped with a handful of melted Cola onions. Then pour Spicy Coca-Cola BBQ Sauce on top and finish with the top bun.
Enjoy with chips, pickles and a cold Coca-Cola.