Finely dice the red onion and mince the thyme, garlic, and chives.

Heat 1 tablespoon butter in a skillet over medium heat.

Add red onion, thyme leaves, 3 garlic cloves, and a pinch of sea salt; cook until softened, about 5 to 6 minutes.

Transfer the softened onion mixture to a mixing bowl and let it cool slightly.

Combine freshly ground beef with the onion mixture, Dijon mustard, 2 tablespoons chives, sea salt, and cracked black pepper.

Shape the seasoned beef mixture into 5 large patties.

Bash the black peppercorns in a mortar and pestle.

Toast the crushed black peppercorns in a second skillet over medium heat for 1 minute.

Melt 2 tablespoons butter in the peppercorn skillet.

Add shallots and cook until softened, about 5 minutes.

Add 4 garlic cloves and stir for 30 seconds.

Remove the skillet from the heat and carefully add whiskey.

Carefully ignite the whiskey, then let the alcohol burn off until nearly evaporated.

Pour in beef stock and heavy cream, then season the sauce with sea salt.

Simmer the sauce, stirring occasionally, until thickened and reduced.

Heat neutral oil in a clean skillet over medium-high heat.

Sear the beef patties until deeply browned on the first side.

Flip the patties and add 4 tablespoons butter, rosemary, and 3 garlic cloves.

Baste the patties with the foaming herb butter until cooked to the desired doneness.

Spoon whiskey peppercorn cream sauce onto plates and place a beef patty over each portion.

Serve with crispy fries or mixed vegetables, then garnish with remaining chives and lemon wedges.