Preheat oven to 180ºC. Slice the mushrooms 1cm thick and cut in half again.
In a heavy-based casserole pot, heat 2 tbsp oil over a low heat. Add the onion, garlic, sage and 1 tsp salt and sauté for 10 minutes until softened. Increase heat, add the mushrooms and sauté until golden. Remove from pot and set aside.
Combine the flour, 1 tsp salt and a grind of black pepper in a bowl. Coat the beef in this a few pieces at a time, making sure all sides are coated and any excess flour is removed.
Heat the remaining oil on high in the casserole pot, add the meat a few pieces at a time, and brown on all sides. Add the carrot, then put the mushroom and onion mixture back into the pot and heat through. Add the ale to deglaze the pot. Add the stock and bring to a boil.
Cover with a lid, transfer to the oven and bake for 1 1/2 hours, until the meat is tender. Serve with crusty bread.