Pat the roast completely dry. Combine seasoning ingredients and massage onto all sides of the roast, then coat with flour.
Heat olive oil in a large pan over medium-high heat. Add the roast and sear on each side for 2-3 minutes until a brown crust forms. Remove from heat and set aside.
Whisk together the gravy ingredients. Pour some gravy into the pan used to sear the roast, scraping the bottom for flavor. Transfer the mixture to a slow cooker, add the roast and any juices.
Cut potatoes and peel/slice carrots. Arrange around the roast in the slow cooker.
Cover and cook on high for 5-6 hours or low for 8-10 hours. Resist opening the lid.
Carefully remove vegetables and roast, placing them on a serving platter.
Transfer cooking juices to a saucepan or stovetop-safe crock. Bring to a boil. Whisk corn starch with cold water, gradually add to the gravy, whisking continuously. Simmer on low until thickened. Add Kitchen Bouquet for a darker color, swirl in cold butter before serving.
Season vegetables with salt and pepper if desired. Serve the roast and vegetables with the prepared gravy. Enjoy!