Heat up a heavy 10-12 inch aluminium skillet over a medium flame. Sear the steak, on both sides. Test it for doneness by poking it. It should put up some resistance. Remove the steak from the pan.
Add the diced bacon to the pan. Render the bacon over a medium-low flame. Drain the mustard seeds, throw them in and saute, until they emit an pop. Add the sliced onion. Season with salt, sweating the onions down. Turn off the flame. Add the vodka and stand back. Ignite the vodka with a long match or a firestick. Allow the inferno of flames to die down. Turn the flame back on. Scrape the bottom of the pan to liberate pan residue. Pour any accumulated juices from under the steak back into the pan. Throw in the heavy cream. Reduce the sauce - slightly. Add the mustard. Reduce until the sauce coats the back of a spoon. Adjust for seasoning with black pepper. Immerse the steak into the pan sauce. Place the steak on a platter. Drench it in sauce.