Heat 1 tablespoon of oil in a large skillet over medium-high heat.

Sear the 3 lb beef roast on all sides until nicely browned. This step adds extra flavor but can be skipped if you’re short on time.

Place the browned roast into your slow cooker.

Pour 1 cup beef broth into the skillet and scrape up all the browned bits from the bottom. This adds incredible depth to the gravy.

Sprinkle 1 packet gravy mix, 1 packet onion soup mix, 1 tablespoon minced garlic (or 3 cloves, minced), and 1 teaspoon black pepper evenly over the roast.

Pour the deglazed broth from the skillet over the roast, then add 1/4 cup red wine vinegar.

Cover and cook on low for 8–10 hours, or until the beef is tender and easily shreds with a fork.

Remove the roast and shred it, then return the meat to the slow cooker.

In a small bowl, mix 2 tablespoons of cornstarch with 1/2 cup cold water until smooth. Stir this mixture into the slow cooker.

Turn to high and cook uncovered until the gravy thickens to your desired consistency.

To serve, place 6–8 slices of garlic toast on plates, top with about 4 cups of prepared mashed potatoes, then spoon the shredded beef and gravy over everything.