- Heat oil in stovetop-safe slow cooker cookware over medium-high heat. Brown roast on both sides. Remove roast from cookware; set aside.
- Add onions and garlic to cookware. Cook until just beginning to soften, about 3 minutes.
- Sprinkle beef with salt and pepper. Place beef on top of onions and garlic.
- In a small bowl, combine flour and beef stock. Add beer and pumpkin pie spice. Pour around beef in cookware.
- Cover and place cookware on slow cooker base. Cook on HIGH for 2 to 2 1/2 hours or on LOW for 4 to 4 1/2 hours. Add sweet potatoes to cookware, arranging around beef. Cover and cook an additional 2 to 2 1/2 hours on HIGH, or 4 to 4 1/2 hours on LOW.
Test Kitchen Tips:
- If using a slow cooker with crock, brown meat and cook onions and garlic in a large skillet over medium-high heat. Transfer ingredients to slow cooker crock and cook as directed.
- Sweet potatoes can be added at the beginning of cooking time, but will be very soft.
- Carrots, potatoes or other root vegetables may be substituted for sweet potatoes.