Bangers and mash with shallot and Marmite gravy and champ

Cut unpeeled Yukon gold potatoes into small chunks, cover with water in a pot, lid on, and bring to a boil over high heat; take the lid off once boiling so it does not bubble over.

Slice the shallot very thin. Heat a little oil a little under medium and add the shallots.

Stir constantly so the shallots caramelize evenly, 5 or 6 minutes.

Push the shallots to the far side of the pan, nudging them so they don't burn, and move the pan so they are off the heat. Add the sausages, one per person.

Brown the sausages all over by rolling them, about seven minutes over medium to medium-low so the fond does not burn.

Deglaze the fond with water and stir in a giant spoonful of Marmite.

Mix the cornstarch with a little water into a smooth slurry; drizzle it in while stirring until the gravy is as thick as wanted. It thickens as it approaches a boil.

Grind in plenty of pepper and add a big spoonful of English mustard. Taste and add a little salt.

Simmer the sausages in the gravy until cooked inside.

Slice the green onions very thin at the white end and wider into the greens.

When the potatoes fall apart, drain through the pot lid. Add a big knob of butter, a splash of milk and a pinch of salt; mash, adding more milk if too thick.

Stir in the green onions; the heat of the potatoes cooks them a bit. Season with more salt.

Plate the mash with a well in the centre; check the sausage is cooked through by cutting it or taking its temperature, 160 F, 70 C. Pour over the hot gravy.