Prepare the black peppercorns by toasting them until they crackle and are fragrant. Ground them and reserve for later use.
Combine all the sauce ingredients in a bowl and reserve for later use.
Pan-fry your steak to your liking, then remove from the pan to rest.
Using the same pan with steak fond, saute onion and garlic over low heat until soft and golden.
Stir the sauce ingredients and pour over the browned onion mixture.
Let it come to a boil and then lower the heat to a simmer and let the sauce thicken to your desired consistency. If it's too thick, add water to dilute; if too runny, let it cook down to thicken. I like mine just coating the spoon.
You can pour sauce directly on top of your steak or place it in a gravy boat.
To add finesse, heat a shot of brandy until it flames, then pour it over the sauce and steak. Your date would be impressed!