Pull the steaks out of the refrigerator 20 minutes prior to cooking.
Heat a large cast-iron skillet over medium-high heat. Sprinkle the steaks with 2 teaspoons each salt and pepper and the flour.
Add the oil to the hot skillet and sear the steaks on both sides, 2 minutes per side.
Reduce the heat to medium and add the butter. Continue cooking for 4 minutes, or until the steaks reach an internal temperature of 135 degrees F.
Remove the steaks from the skillet, tent with foil and let rest.
In the same skillet, add the onions, mushrooms, parsnips and thyme; cook until the vegetables begin to soften, 3 to 5 minutes. Add the tomato paste; cook for an additional 5 minutes.
Deglaze the skillet with the red wine, beef stock and sherry. Cover and simmer over low heat for 10 to 20 minutes. Stir in the lemon juice.
Slice the steak and smother with the sauce.
This recipe was created by a contestant during a cooking competition. It has not been tested for home use.