English Bangers and Mash with Onion Gravy Recipe

Place potatoes in a saucepan and cover with cold water. Season well with salt. Bring to a boil over high heat, reduce to a simmer, and cook until potatoes are soft, about 10 minutes. Drain and place back in saucepan, add 3 tablespoons butter and 2/3 cup milk, and mash with a potato masher, adding more milk if a looser consistency is desired. Season to taste with salt and pepper. Keep warm. Heat remaining 3 tablespoons butter in a large non-stick skillet over medium-high heat until melted. Add onions and bay leaf and cook, stirring often, until onions are brown, about 15 minutes. Sprinkle with flour and mix until flour is evenly incorporated with onions. Stirring constantly, slowly pour stock over onion mixture. Bring to a simmer over high heat, stirring often, then lower heat to medium and cook until thickened, about 6 minutes. Remove and discard bay leaf. Season to taste with salt and pepper, and keep warm. Heat vegetable oil in a large stainless steel skillet over medium high heat until shimmering. Reduce heat to medium-low. Place bangers in the skillet and cook until browned on one side, about 5 minutes; flip bangers and cover. Cook until bangers are fully cooked, about 6 minutes longer. Divide mash between 4 plates, place 2 bangers on each pile of mash, and top with onion gravy. Serve with brown ale and extra gravy and strong mustard passed alongside.