Onion And Anchovy Pizza (pissaladière)

Heat the butter in a large frying pan. Add the onions and a little salt and pepper and cook over low heat for about 20 minutes, stirring from time to time, until lightly caramelised. It’s important to cook the onions slowly as otherwise they can burn and taste unpleasant. Leave to cool slightly.
Preheat the oven to 190°C and lightly brush a large square or rectangular tray with some of the oil.
Place the dough on the tray and use your hands to flatten it out to a rough square or rectangle about 5 mm thick. Brush the top of the dough with a little more oil.
Spread the cooked onion on top leaving a border of about 2 cm around the edges. Form the anchovies into lines about 5 cm apart going diagonally across the onion. Make more lines of anchovies criss-crossing these lines, creating a diamond pattern. Place an olive and thyme sprig in each diamond. Season the pissaladière with pepper.
Bake in the oven for about 15 minutes, or until the base is golden and crisp. Brush the edges of the bread with a little more olive oil, then slice and serve. (Alternatively, let the pissaladière cool to room temperature before serving.)