Heat a large cast iron skillet to high heat. Season the flank steak high and aggressive with kosher salt and freshly cracked black pepper. Add a drizzle of olive oil to coat the pan and 1 tbsp butter.

Place the steak into the cast iron skillet and sear it until golden brown, about 5-7 minutes on each side. Turn the heat to medium-high if the skillet is getting too high. You will want to sear it on both sides until the steak is about medium-rare to medium. Then remove the steak to a cutting board to rest while you make the sauce. Tent the steak with foil, do not cover all of it or it will steam and you will lose the sear you created on the steak.

Turn the pan down to low, add in the sliced shallots and saute until they begin to lightly brown and soften. Add in the fresh thyme and the stock. Bring to a boil and slightly reduce by about a 1/4. Then add in the wine and reduce by 1/2.

Whisk in the dijon mustard and cook until slightly thickened. Turn off the heat and whisk in the butter. Garnish with the chopped parsley, if using.

Slice the flank steak, against the grain and spoon the pan sauce over the top. Serve immediately with a light salad of arugula and lemon with some shaved Parmesan. ENJOY!