Make your pan hot. If you’re pan-searing, heat a skillet over medium-high heat until it’s singing. If you’re grilling, have the grill ready to roar.
Sauté garlic in a touch of oil for 30 seconds. Don’t burn it—garlic ash is not delicious in a sauce.
Pour in stock, Worcestershire, soy, ketchup, Dijon, and brown sugar. Stir to combine and bring to a gentle simmer.
Stir in the cornstarch slurry to thicken. Let it simmer for 2–3 minutes until the sauce coats a spoon. If it’s too thick, splash in a little more stock.
Turn off the heat and whisk in butter for shine. Season with salt and pepper to taste. Taste once, then adjust—because you’re the boss here.
Pour over the resting steak or serve on the side for dipping. Your call, drama-free.