Heat your galley oven so it's just warm. That will be for keeping the steaks warm while you prepare the sauce. You don't want them to cook, so just keep it very low. (or skip that and just cover the steaks loosely with foil.)
Mince the shallots and set aside.
Pat the filets dry and season with kosher salt. Coarsely crush black pepper corns with a hammer or the back of a cast iron pan. You'll want to put them in a tough ziplock bag so they don't go flying all over your cabin. Press the peppercorns into the filets.
Heat olive oil and 1 tablespoon butter in a skillet. Add the filets and sauté for about 3 minutes per side for medium rare. 6 minutes total. They should still fell very "squishy" when you press your finger into them.
Transfer to an oven proof dish. Turn off your oven and place the steaks in the oven to stay warm. Ot just cover them with foil. They should not continue to cook.
Return to the skillet and add two tablespoons of butter to the existing oil. Once it starts to bubble, sauté the shallots. Whisk the Better Than Bouillon into the cream so it's dissolved. When the shallots have softened add the cream mixture to the pan and heat to a low simmer. Add the brandy and let simmer for about 5 minutes until reduced to almost half. Turn off the burner and blend in the last two tablespoons of butter.
Serve the sauce with the filets and enjoy. A glass of red wine will balance out the perfect evening!