Cut the meat into 1-inch cubes, trimming away any large pieces of fat—marbled fat throughout the meat is perfectly fine and adds flavor.

Season the beef with black pepper, garlic salt, and celery salt, tossing to coat evenly. Sprinkle the flour over the seasoned meat and toss again to ensure it’s well coated.

In a large skillet over medium-high heat, heat 3 tablespoons of olive oil. Working in batches to avoid overcrowding, brown the beef on each side for about 45 seconds. Add more oil as needed between batches. Once browned, transfer the beef to the slow cooker.

Reduce the skillet heat to medium and melt 1 tablespoon of butter. Add the diced onions and cook for 5 minutes until softened. Stir in the minced garlic and cook for another minute. Pour in a splash of the wine and use a silicone spatula to deglaze the pan, scraping up the browned bits from the bottom—this adds rich flavor to the stew. Transfer the onion and garlic mixture into the slow cooker with the beef.

Add the rest of the ingredients to the slow cooker, except the peas, the cornstarch mixture, and the remaining 2 tablespoons of cold butter.

Cover and cook on low for 7½ to 8 hours, or on high for 3½ to 4 hours, until the vegetables are tender and the potatoes are easily pierced with a fork.

Stir in the peas during the final 15 minutes of cooking. Discard the bay leaves and the rosemary stem before serving.

To thicken the stew, if desired, mix ¼ cup cold water with 3 tablespoons of cornstarch and slowly add it to the pot, stirring until well combined. The stew will continue to thicken slightly as it sits.

Turn off the heat and swirl in the remaining 2 tablespoons of cold butter for a smooth, glossy finish—this chef’s technique is known as “Monter au Beurre.”

Optional: For a richer, darker appearance, stir in 3 drops of Gravy Master.