Mix in your robot the flour, water (with baking yeast), olive oil and salt. When you got a nice pasta, cover with a towel and leave for 1 hour.
In the meantime slice the onions and cook the onions with 2 anchovies and the unpeeled garlic cloves for around 45 minutes in a pan covered with olive oil.
Preheat your oven to 200°C (400°F).
Spread the pasta on a baking tray covered with greaseproof paper.
Spread the onions.
Add on top the olives, unpeeled garlic cloves and the rest of the anchovies. Bake for around 30 minutes.