Carefully select the mussels and throw away any opened mussels. Brush the closed mussels thoroughly under running water and remove the beards. Drain on a colander.
Put 2 tablespoons of oil in a large saucepan, add the dripping wet mussels and heat until all the mussels have opened. Break open the shells, remove the inner beard and peel off the upper shell of the clams.
Peel the garlic cloves, weigh them finely and mix with the parsley, breadcrumbs, the remaining oil and salt and pepper. Set the oven to 200 &