Add oil to a large cast iron or stainless steel skillet over medium heat. Add thinly sliced onions and toss them to coat with oil. Add 1 teaspoon salt then stir one more time.
Cook the onions, stirring and scraping up the bottom of the pan every 5 minutes with a wooden spoon. Cook for 25-35 minutes. Around 20 minutes onions will start to smell caramelized. Around 30 minutes onions should be blonde in color and thickened. Cook longer for a deeper caramelized flavor or move on once to your liking. Turn down heat if you notice they are cooking too quickly or burning.
Add the burgers to the pan with the onions and salt and pepper to taste. Begin chopping until they are a crumbled like texture. Cook 10 minutes or according to the packaged instructions. Should reach 165˚F. *Alternatively, remove the onions if desired as a topping, but cook the burgers in the same skillet.
Once crumbled and heated through, add four slices of cheese on top. Add skillet lid and remove from heat. Let sit for about 3-4 minutes or until cheese has melted.
Add ¼ of the mixture to a hoagie roll with lettuce, tomatoes and your favorite condiments. Serve and enjoy!
Notes
**Nutritional facts are just estimates. Please utilize your own brand nutritional values to double check against our estimates.