Mashed Potatoes with Mushroom & Caramelised Onion ‘Lice’

Immersive Ten Plagues Seder Menu: Plague 3 – Lice

Serves 6

Prep time: 30 mins | Cooking time: 30-45 mins

The Egyptians tormented the Israelites by forcing them to sweep dirt from the streets, and when the third plague struck, that same dust turned into lice tormenting the Egyptians.According to the Yalkut Shimoni, a mixture of 24 different forms of lice struck Egypt ranging in size from a hen’s egg to a goose egg. Our larger-than life ‘lice’, however, are a delicious mixture of mushrooms and onions strewn across fluffy mashed potatoes. Who said potato was boring?! 


  • 1.5kg-2kg (4lb) Potatoes
    (A good, floury all-rounder like Maris Piper, King Edward or Rooster works
    perfectly. Avoid waxy potatoes like Charlottes and Jersey Royals.)
  • 80g (⅓ cup) Margarine
    (or Extra Virgin Olive Oil if preferred)  
  • 3 small Red Onions very finely diced
  • 150g (¾ cup) Mushrooms finely diced(we used chestnut mushrooms for their colour and earthy flavour)
  • 1 tsp Garlic Powder 
  • 1½ tbsp Salt (adjust according to taste)
  • Black Pepper to taste
  • 1 tbsp Oil


  1. Peel and chop your potatoes into small cubes, approx 2.5cm (1″) in size.
  2. Fill a large pot with well-salted water, and add the potatoes—the salt helps to remove starch from the potatoes and also adds flavour. This is the only salt we added to the potatoes. Make sure there is enough water to cover the potatoes completely. 
  3. Bring to the boil and reduce to a simmer–this will result in the potatoes cooking through evenly. 
  4. Cook until soft enough to break easily with a fork—approximately 20 mins.
  5. Meanwhile, add ½ tsp of salt to your finely chopped raw onion and mix. 
  6. Heat 1 tbsp of oil in a pan and add onions. Gently cook down your onions over a medium heat until soft. 
  7. Add in your mushrooms and 1 tsp of garlic powder. Stirring regularly, continue to cook down until mushrooms are soft and onions start to caramelise. Around 10-15 mins. 
  8. Turn the heat off and set to one side. Your potatoes should now be close to, if not completely ready. Check that they are soft enough to break easily, remove and drain from the heat when ready. Put into a pan or bowl that doesn’t scratch easily and mash with a potato ricer or masher. 
  9. Add in your margarine (or oil) and black pepper (for both flavour and extra lice effect) and then mix together, mashing and fluffing up with a fork.
  10. To serve, plate the potatoes in a bowl or dish, and top with your very tiny (and
    utterly delicious) ‘lice’ mixture, sprinkling extra round the edges for dramatic effect!

Both the potatoes and the mushroom/onion mix can be made in advance.
Store and heat separately before serving.

Leftovers can be reheated or spun into potato croquettes—check out the recipe at

Photo credit: Sophy Weiss Photography

Mashed Potatoes with Caramelised Onion and Mushroom 'Lice'