Pat the beef dry all over with kitchen paper. Put the ghee in a large heavy-based pot set over a moderate-high heat then sear the corned silverside on all sides, until well-browned. Set aside.
Add the onions, bay leaves, fennel seeds, peppercorns and ginger to the saucepan and cook for 5 minutes, until the onions begin to soften. Pour in the ginger beer and stock, then return the corned silverside. Bring to a simmer, then cook for 3 hours with the lid on, until the corned silverside is very tender.
Strain the cooking liquid into a second saucepan and boil rapidly until reduced by three-quarters. In a third saucepan, cook the butter and flour until it resembles wet sand, then pour in the reduced cooking liquid and cream. Simmer for 5 minutes, until thickened, then season with salt and pepper. Fold in the chives.
Shred the corned silverside and serve with the sauce and roasted vegetables.