Clean, wash and drain the mussels. Sort out open mussels. Peel and halve onions, then cut into fine strips. Clean, wash and cut the leeks into rings of about 1 cm width.
Wash tarragon, shake dry. Pluck off leaves and chop finely. Peel garlic and cut into fine slices.
Sweet potatoes peel, wash, grate dry and cut into about 1 cm thick sticks. Mix mayonnaise with mustard, lemon juice and honey. Season dip with salt, pepper and honey.
Heat the fat in a frying pan and fry the vegetables, garlic and tarragon for approx. 3 minutes until the onions are translucent. Add the mussels and fry. Deglaze with beer. Season with salt and pepper.
Simmer covered for approx. 10 minutes until almost all mussels are open and remove closed mussels.
In the meantime heat the oil in a wide pot. Fry the potato pegs in it in portions until crispy. Let them drip off on kitchen paper. Sprinkle with salt. Arrange mussels, add sweet potato fries and mayo dip.