Place a large pot on the hob and get it quite hot. Add the mussels, put the lid on and shake the pot.
The mussels should be open and be cooked in a minute or two. Remove the mussels and strain the liquid through a fine sieve. Set both aside.
Give the pan a quick rinse and sweat the onion and leek in half the butter until just soft.
This should take 3 to 5 minutes.
Drain the oats and add them to the pot.
Season with salt and pepper.
Stir then add the mussel stock and a little water if required.
You are aiming for a thick porridge consistency.
Taste the oats as you go and keep stirring, as it is prone to sticking.
After 10 to 15 minutes cooking and stirring, add the cockles to the pot and cover with the lid.
The shellfish will open with the heat of the cooked oats.
Then add the cooked mussels and season with salt, pepper and good squeeze of lemon juice.
Stir in the remaining butter.
Be gentle with this dish - don’t mix it too much but do be careful of sticking.
Spoon the brose into warm bowls and garnish with parsley and pepper dulse seaweed.
