Cut meat into 1-inch cubes, discard any large pieces of fat. Fat marbleized into the meat is fine!

Sprinkle beef with black pepper, garlic salt, and celery salt. Toss to coat. Sprinkle flour over the meat and toss again.

Heat 3 Tablespoons olive oil in a large skillet over medium-high heat. Add the meat in batches, don’t overcrowd the pan. Brown on each side for 45 seconds. Add more oil if needed. Transfer to slow cooker.

Reduce heat to medium and melt 1 tablespoon of butter. Add onions and cook for 5 minutes. Add garlic and cook for 1 minute. Add a splash of wine and use a silicone spatula to loosen the brown bits in the skillet, this will add more flavor to the stew. Transfer the onions, garlic, and remaining wine to the slow cooker.

Add all remaining ingredients except for the peas, corn starch mixture, and 2 tablespoons of cold butter.

Cook on low for 450 minutes or high for 240 minutes, until the vegetables are softened and the potatoes are fork tender.

Add the peas during the last 15 minutes of cooking. Remove the bay leaves and rosemary stem.

Optional: To thicken, combine ¼ cup COLD water with 3 Tablespoons of cornstarch. Slowly add it to the stew, stirring to incorporate. It will continue to thicken upon standing.

Turn off the heat. Swirl in 2 tablespoons of cold butter for a smooth, velvety finish. This is a technique that chefs use called 'Monter au Beurre'. Optional: Add 3 drops of Gravy Master for an even darker color.