1. Rinse the corned beef and pat it dry using a paper towel.
2. Heat a large skillet over medium-high heat and add the cooking oil to coat the bottom of the pan. Once the oil is hot, sear the meat on all sides until browned. Transfer the browned meat to a slow cooker.
3. In a small bowl, combine the maple syrup, mustard, black pepper, and minced garlic clove. Stir well.
4. Pour the sauce over the corned beef in the slow cooker.
5. Cover the slow cooker and cook on LOW for 7 hours.
6. Serve!
