Preheat oven to 350º. Verify rack is in the middle position of the oven.
In a small bowl, combine rub ingredients.
Pat dry pork steaks with a paper towel and apply rub on both sides of the steaks. Press in the rub. Allow steaks to acclimate for 20 minutes.
Heat a 12", oven safe skillet to medium heat - I used a cast iron skillet.
When oil is hot, brown pork steaks, so they are brown on both sides, but not cooked through, about 7 minutes per side.
Remove pork from skillet and place on a plate to collect residual juices.
With the remnants of the pork, now in the skillet, add the butter.
Once butter is melted, add the onions and cook until they are brown, turning occasionally.
Stir in garlic and thyme. Cook for an additional 30 seconds.
Add beef broth and bay leaf. Stir onions, scraping up any brown bits in skillet and return to a boil.
Return pork steaks to skillet, along with any accumulated juices.
Cover with a lid - or aluminium foil and place in the oven.
Cook for 45 - 60 minutes, till steaks reach an internal temperature of 165º.
Remove from oven and return to cook top.
Remove pork steaks from skillet and place on a plate. Cover with foil to keep warm.
Using a strainer and fat separator, reserve onions and pour sauce in separator in order to remove fat.
Skim off any residual fat.
Pour sauce back into skillet and bring to a boil.
Reduce heat to a simmer. Mix 1 Tablespoon of beef broth and the cornstarch in a small bowl till combined, then whisk into skillet.
Stir in reserved onions and vinegar.
Serve ideally with mashed potatoes.