Tip : You could substitute beef consommé for the demi-glace, but if you do, you will have to thicken the sauce with a flour and water slurry or cornstarch. See my notes at the end for sources for demi-glace, which would really be the best for this recipe.
Gather all ingredients before starting the recipe.
Using a meat mallet, pound each slice of pork to a 1/4" thickness and season with kosher salt. Set aside until after the Jäger sauce is simmering.
Jäger Sauce
Cut 1/2 lb bacon into lardon, or 1/4" pieces
Chop 1/2 medium onion and slice 2 cups sliced cremini mushrooms.
Heat 1 tbpn olive oil in a deep sided skillet over medium heat and add the bacon. Sauté until most of the fat has rendered from the bacon, about 6-8 minutes.
Add the chopped onion to the bacon and sauté for another 4-5 minutes, or until the onions have become translucent.
Turn the heat to medium high and add the sliced mushrooms, cook stirring frequently until the mushrooms begin to brown, about 4-5 minutes.
Add 1/4 cup red wine to deglaze the pan, stirring to scrape up all the brown bits and cook until the wine has been reduced by half.
Add 1 cup Demi Glace (see notes) and stir to combine then reduce heat to medium low. Simmer gently while you are preparing the schnitzel.
Schnitzel
Heat 1-2 tablespoons olive oil for frying in a non-stick skillet over medium high heat until the oil is shimmering.
Dredge each slice of pork loin in flour and add to hot skillet. Fry the pork slices for about 2 minutes per side or until they turn a nice golden color.
Transfer cooked pork slices to a platter and reserve.
Finishing
Swirl in 2 tbsp unsalted butter and 2 tbpn chopped parsley into the Jäger sauce and stir until the butter has been fully incorporated.
Serve the schnitzel slices topped with the Jäger sauce.