Scallion Champ with Sausages

From the garden

• 2 bunchs green onions, thinly sliced, greens and whites together
• 2½ lb floury potatoes (russet or Yukon Gold), peeled and cut into even chunks
• 2 large yellow onions, halved and thinly sliced

From the pantry

• 1 cup whole milk
• 6 tbsp butter · divided; most goes in the mash, the rest melts in the well
• 8 fresh pork sausages · Italian sausage links are the easiest stand-in for bangers
• 1 tbsp all-purpose flour
• 1½ cups chicken stock · beef stock if you have it
• 1 tsp Worcestershire sauce
• 1 tsp Dijon mustard
• salt · to taste
• black pepper

1. Simmer the sliced green onions in the milk over low heat for 5 minutes, then pull the pan off and let them steep while the potatoes cook. This gentle infusion is the step that makes champ champ.
2. Cover the potatoes with cold salted water, bring to a boil, and cook 18–20 minutes, until a knife slides through with no resistance. Drain, then return them to the dry pot over low heat for a minute to steam off.
3. Brown the sausages in a heavy skillet over medium heat, turning every few minutes, 12–15 minutes total, until cooked through and dark in patches. Move them to a warm plate and leave the rendered fat in the pan.
4. Cook the onions in that fat over medium-low with a pinch of salt, about 12 minutes, until collapsed and sweet. Stir in the flour, then the stock, Worcestershire, and mustard, and simmer 4–5 minutes until the gravy coats a spoon.
5. Mash the potatoes with the warm scallion milk and 4 tablespoons of the butter until fluffy but still a little rough. Season hard with salt and pepper; underseasoned mash tastes of nothing.
6. Pile the champ into wide bowls, press a well into the middle of each, and drop in the remaining butter. Lean the sausages against the mash, pour the onion gravy over, and eat from the outside in.