Deep-Fried Mushroom and Quinoa Burger with Purple Sauerkraut and Garlic Mayonnaise

Yield: 6 burgers

Ingredients

Burger mixture

  • 4 medium shallots\
  • 2 tbsp rapeseed oil\
  • 2 tbsp dark malt or red wine vinegar\
  • 2 tbsp butter\
  • 400 g (14 oz) field mushrooms, ideally chestnut mushrooms\
  • 2–3 tbsp dry-roasted walnuts\
  • 400 g (about 2 cups) boiled quinoa\
  • 1 tbsp deseeded, finely chopped chilli\
  • 140 g (about 1½ cups) grated Parmesan\
  • 25 g (about ½ cup scant) panko breadcrumbs\
  • 2 eggs

Breading and deep-frying

  • 120 g (generous ¾ cup) plain (all-purpose) flour\
  • 3 eggs\
  • 75 g (about 1¼ cups) panko breadcrumbs\
  • 75 g (about ½ cup scant) boiled quinoa\
  • 1 litre (about 4 cups) peanut oil\
  • Salt

To serve

  • 6 burger buns\
  • Butter for the buns\
  • Purple Sweetheart Cabbage and Apple Sauerkraut\
  • Pickled Mustard Seeds\
  • Garlic Mayonnaise

Instructions

  1. Cook the shallots
    Peel and finely chop the shallots. Heat 1 tablespoon of the rapeseed oil in a frying pan and brown the shallots until they start to develop colour. Pour in the vinegar and reduce to a sticky mixture. Reduce the heat and add 1 tablespoon of the butter. Stir until the butter has melted and the onions are glazed. Transfer to a bowl and allow to cool.

  2. Cook the mushrooms
    Clean and finely chop the mushrooms. Dry out the frying pan in which you fried the onions, pour in the remaining rapeseed oil and heat until the oil starts to smoke. Toss in the mushrooms and flash-fry until they start to develop colour and shrink. Reduce the heat and add the remaining butter. Stir until the butter has melted. Transfer the mushrooms to the bowl with the onions.

  3. Mix the filling
    Toast the walnuts and crush about 2–3 tablespoons in a mortar. Add them to the bowl along with the quinoa, chilli, Parmesan, panko breadcrumbs, and eggs. Stir until everything is well combined.

  4. Shape and chill
    Take a handful of mixture at a time and shape into 6 round patties, either by hand or using a food ring. Put the patties on a large plate and cover with plastic wrap. Place in the freezer for a few hours until firm. This makes breading and frying easier.

  5. Preheat the oven
    Preheat to 180°C (350°F / Gas 4).

  6. Prepare breading stations
    Put the flour in one bowl. Crack the eggs into another bowl and lightly whisk. Mix the panko breadcrumbs and quinoa in a third bowl. Take the patties from the freezer and coat first in flour, then egg, then the panko–quinoa mixture.

  7. Heat the oil
    Pour the peanut oil into a high-sided saucepan and heat to 190°C (375°F). Reduce heat to medium and try to keep the oil at this temperature.

  8. Deep-fry
    Fry the patties 2 at a time for 2–3 minutes, until golden brown. Turn occasionally with a slotted spoon.

  9. Drain and bake
    Lift the patties out and place on a paper-towel-lined plate to drain excess oil. Salt both sides. Transfer to an ovenproof dish and bake for 5–10 minutes.

  10. Toast the buns
    Butter the cut sides of the buns and fry quickly in a pan or toast under the broiler until golden.

  11. Assemble
    Put a little sauerkraut on the bottom of each bun. Add a patty, spoon over some pickled mustard seeds, and finish with a dash of garlic mayonnaise.

Notes

  • Freezing the patties before breading is important for structure.\
  • Keeping oil near 190°C helps prevent soggy burgers.\
  • These pair well with sharp pickles or extra mustard for contrast.