Add the oil to a cast iron skillet and heat to medium.
Add the shallots and cook, stirring every couple of minutes until they begin to caramelize, about 20 minutes. Note: the shallots should cook at a golden-brown hue and shouldn’t burn – if they begin cooking too quickly, lower the heat.
Add 3 tablespoons of red wine and continue cooking until all of the wine has burned off, and shallots are completely caramelized, about 5 to 8 minutes.
Set aside until ready to use.
Cook the mushrooms:
Add the oil to a sauté pan and heat to medium-high.
Add the mushrooms and cook, stirring frequently, until they turn brown and water is seeping out, about 5 to 8 minutes.
Add 1 tablespoon of wine, a sprinkle of salt, and continue cooking until much of the water has burned off and mushrooms are soft, but al dente, about another 1 to 2 minutes.
Make the turkey Burgers:
Heat a cast iron skillet to medium-high with enough oil to generously coat the surface (or fire up the grill).
In a mixing bowl, lightly beat the egg and add the rest of the ingredients for the burgers. Mix everything together well. The meat will be very wet and mushy, but that’s okay.
Form 4 burger patties and place them on the cast iron skillet (or grill), cooking them until the sides of the burger begin to firm up and turn brown. Carefully flip the burgers and continue cooking until they feel firm when poked and are cooked through.
Place slices of swiss cheese on top of the burgers and cook until melted.
Serve with caramelized shallots and mushrooms on a toasted bun.
Notes
You can prepare the shallots and mushrooms in the same pan by adding the mushrooms once the shallots are almost done.