1) In a food processor blitz the sourdough to coarse crumbs. Mix with the olive oil and set aside.
2) Put the ’njuda and the butter in the food processor and blend until smooth.
3) Preheat a broiler/grill.
4) Put some coarse sea salt on a baking tray and nestle in the oyster halves. Spoon a teaspoon of the butter over each oyster and sprinkle over the crumbs.
5) Put the oysters under the grill and cook for 3-5 minutes until golden. Allow to cool for a minute before serving.