In the slow cooker, whisk together the beef stock, Worcestershire, flour, garlic powder, onion powder, thyme, sugar, mushroom powder, and a pinch of salt and pepper.

Stir in the beef, onions, bay leaf and mushrooms. Pour the pepperoncinis on top, then top with pads of butter.

Cover and cook on low for 6–7 hours or high for 3–4 hours, until beef is fork-tender.

30 mins before the cook time is over, mix 2 tablespoons of cornstarch with a few tablespoons of water to make a slurry. Stir it into the slow cooker and cook on high, uncovered, for another 30 minutes to thicken.

Taste and adjust seasoning. Serve hot over mashed potatoes, rice, or noodles.

Add everything to the Instant Pot (except the cornstarch slurry), using 1½ cups beef stock instead of 2 cups.

Seal and set to “Meat/Stew” or high pressure for 35 minutes.

Let the pressure naturally release for 10–15 minutes.

Switch to sauté mode. Stir in the cornstarch slurry and let the gravy bubble and thicken for 1–2 minutes.

Season to taste and serve warm.