Add apple cider, tomato paste, flour, Worcestershire sauce and 1/2 teaspoon of salt to your slow cooker and whisk until combined.
Quarter the potatoes (you can use sweet potatoes or reds if you prefer) and chop the onion. Add them, along with the carrots, to the slow cooker.
Mince the garlic and chop the rosemary; add to slow cooker.
Salt and pepper both sides of your roast, and then nestle into the veggies. Cook on high for 6 to 7 hours.
Serve warm with the juices drizzled on top!