For The Steak

1. Pat down your braising steak and season generously with salt and pepper on all sides. Heat a large skillet over medium-high heat. Add the butter and a splash of oil. When the butter melts and starts to crackle, add the steak to the skillet and sear on all sides for about 2-3 minutes per side. Once done, remove and rest on a plate.
2. OPTIONAL: Add a little more oil to the pan and sauté the onions for 3-4 minutes or until they sweat down just a tad bit.

If Using Slow Cookier

1. Add half the onions to the slow cooker, followed by all the garlic, broth, Worcestershire sauce, apple cider vinegar, onion powder, dried thyme, bay leaf, celery seeds, sugar, and the steak. Top with the other half of the onions. Allow the roast to cook on the low setting for 6-8 hours.
2. Remove the meat from the slow cooker. Cover, keep warm. Combine 2 tablespoons of the cornstarch and water in a small bowl or mason jar. Add to the slow cooker, stir and let cook for an additional 5-7 minutes. If the gravy is still thin, use the remaining tablespoon of cornstarch dissolved in 2 tablespoons of water, let cook an additional 5 minutes.

If Using Oven

1. Position a rack in the center of the oven and preheat the oven to 135C. Once you sauté the onions, add the steak back in to the dutch oven along with the garlic, broth, Worcestershire sauce, apple cider vinegar, onion powder, dried thyme, bay leaf, celery seeds, and sugar. The liquid should come half way up the steak, if it doesn't add additional broth until half of the steak is submerged. Stir to combine. Cover the dutch oven with a lid and let braise in the oven for 1 hour and 15 minutes. Remove the pot from the oven, check for doneness and continue braising for an additional 1 to 1 ½ hours. Your roast it done when it easily pierces with a fork.
2. Remove the meat from the dutch oven. Cover, keep warm. Combine cornstarch and water in a small bowl or mason jar. Heat the dutch oven over the stove on medium-high heat until the liquid reaches a simmer. Add the cornstarch mixture to the pot while stirring. Let the gravy regain a simmer. If the gravy is still thin, use the remaining tablespoon of cornstarch dissolved in 2 tablespoons of water, let cook an additional 1-2 minutes.