Cook the eggs in boiling water for 6-7 minutes. Wash the tarragon, shake dry and finely chop the leaves. Peel and finely dice the onion . Wash the spinach and drain in a sieve.
Heat the oil in a pan and fry the onion over a medium heat. Add the soy cream and bring to the boil.
Add the spinach to the pan and simmer for 2 minutes.
Add the mustard and tarragon, mix well and season the sauce with salt, pepper and Tabasco.
Drain the eggs, cool under cold water, then peel. Heat the eggs in the mustard sauce and serve with mashed potatoes.