Beef Medallions with Caramelized Pan Sauce

Season beef medallions with salt and pepper to taste and set aside.

Heat vegetable oil in a skillet over high heat.

Cook beef until browned, about 2 minutes per side.

Remove beef to a warm plate.

Reduce heat to medium; cook and stir mushrooms, 1 tablespoon unsalted butter, olive oil, and a pinch of salt in the skillet until mushrooms are very well browned, about 10 minutes.

Mix in tomato sauce; cook and stir until tomato sauce thickens, about 5 minutes.

Pour in Marsala wine and increase heat to high.

Cook, scraping browned bits from bottom of skillet.

Once most of the wine has evaporated, stir in broth and bring to a boil; cook and stir until broth mixture has reduced by half, about 5 minutes.

Reduce heat to low and return beef to broth mixture; simmer until beef is cooked to medium-rare, about 2 to 3 minutes.

Transfer beef to serving plates.

Remove skillet from heat.

Cook and stir 1 1/2 tablespoons butter and oregano into the sauce until butter melts.

Taste for seasoning and adjust if necessary.

Spoon sauce over beef and serve immediately.