To make caramelized onions, chop two big onions in half, peel them, and then chop them into half-moon shapes.
Take a skillet. Place it over a medium-high flame. Heat one tablespoon of canola oil and sauté onions for 20-25 minutes, or until golden brown. stirring frequently.
Reduce heat to medium if onions are browning too soon. Add a bit extra water or oil if the liquid evaporates. To prevent the onions from burning, you need some sort of liquid.
Heat the frozen caramelized onions over medium heat. After they're warm, transfer to a dish and cover with foil.
Use the same pan to cook the same burger and eventually, the patty melts.
Now take the ground beef, preferably grass-fed, and divide it in fourths.
Since the meat will shrink when it cooks, form an oval patty that is slightly larger than the bread.
Transfer to a baking dish lined with parchment paper, season one side with salt and pepper, and freeze for ten to fifteen minutes.
Assemble the remaining ingredients and make any side dishes you want to serve while you freeze the patties.
For medium-rare, cook the burgers on a stovetop grill over medium-high heat for two to three minutes on each side. As soon as you notice the juice rising to the top, flip. Take out once cooked.
Arrange a slice of bread with the cheddar cheese, then top with a hefty heaping of caramelized onions, cooked burger, Swiss cheese, and another slice of rye bread. Spread mayonnaise or softened butter over one slice of rye.
Reduce the heat to medium. Use a paper towel to wipe the pan clean. Reposition the sandwich on the pan, mayo side down, and cook it on the griddle much like a grilled cheese. Brush the top with mayonnaise and turn once the bottom bread is golden, roughly 3 minutes on each side, just long enough to toast the bread and melt the cheese.
Your Waffle House Patty Melts are ready. Bon Appetit!