Bring a large pot of well-salted water to the boil. Wash the potatoes well then cut into ~3cm chunks. Drop them into the boiling water, bring the water back up to the boil and cook for 3 minutes. Remove the pot from the heat and drain the potatoes.
Over a medium-high heat, heat a large frying pan with enough oil to coat the base of the pan well. Once the oil is hot add the potatoes to the pan and season with some salt - you don't want to crowd it too much so you may need to fry in 2 batches, depending on the size of your frying pan.
Cook the potatoes until they start to turn golden underneath then turn them so all the sides become golden. Remove from the heat and set aside.
On a serving plate, lay down the rocket leaves. Mix the cannellini beans, pesto and olives together in a small bowl and distribute over the leaves. Lay on the tomatoes and warm potatoes. Place the burrata in the centre and sprinkle with the za'atar and basil leaves. Serve.