• Place a large skillet on stove top and heat over medium high heat (perferably a non-stick skillet).
• Add 2 Tablespoons of olive oil.
• Generously sprinkle salt, pepper, and garlic salt on all sides of the pot roast.
• Place roast in hot oil on a skillet and let it sear on that side for 2 minutes. Flip the roast over and sear the other side for 2 minutes.
• Depending on the shape of your pot roast, you can sear the other sides if you choose.
• Spray the slow cooker with non-stick cooking spray and place your seared pot roast in the slow cooker.
• Add the remaining tablespoon of olive oil to the hot skillet. Add onion, carrots, and celery to the skillet and season with more salt and pepper, if desired. Using a spatula, scrape the "brown bits" (aka the burnt bits) off the bottom of the skillet as you cook the vegetables (these bits add so much flavor!).
• Cook for about 3 minutes or until the vegetables start to soften.
• Add garlic to the skillet and cook for 1 minute more.
• Add the vegetables to the slow cooker, spreading the vegetables all around the roast.
• Pour in the beef broth, being sure not to pour it directly on the roast  or vegetables because you just cooked them in delicious flavors. Try to pour the beef broth on the sides as much as possible.
• Pour the Worcestershire sauce, balsamic vinegar, and soy sauce directly on the roast. Sprinkle thyme and rosemary evenly around the meat and vegetables.
• Place the lid on top of the slow cooker and set timer for 8-10 hours on low heat (it will vary based on your slow cooker - mine is done in 8 hours, but some will take longer) or 4-5 hours on high heat (I highly recommend cooking this roast on low - I have never had it turn out as well when I have cooked it on high.
• Remove roast from slow cooker and slice into pieces (it should pretty much fall apart by this point).
• Serve with mashed potatoes and the cooked carrots on the side.

Gravy

• When the roast is done cooking, use a baster (or whatever method you want) to remove the liquid from the slow cooker. To make gravy, you will want to get at least 3 cups of drippings from the slow cooker. If you don't have quite enough drippings, you can supplement with a can of beef broth or beef stock (I like to use beef stock for gravy because it's a little more flavorful).
• Place a small saucepan on the stovetop over medium heat.
• Add butter to the saucepan and let it melt.
• Add flour and use a whisk to whisk flour and melted butter together until it makes a paste (takes about a minute).
• Pour in the drippings, whisking the entire time.
• Cook for about 4-5 minutes minutes or until the gravy reaches the thickness you prefer.
• Serve roast with gravy on top and on top of mashed potatoes.