Preheat the oven to 240C. Dust a heavy baking tray with flour.
In a large bowl sieve the bread soda with the flour and salt.
Make a well in the centre. Add the buttermilk. Use your hands or a round bladed knife to bring the dough together until it is craggy and soft.
Wash your hands. Transfer the dough to a floured surface and roll into a rectangle.
Brush a swiss roll tin with olive oil and place the dough into the tin pressing it gently to fit.
Spread 2 tbsp sauce over the base leaving the edges clean. Arrange the parma ham and mozzarella over the pizza base. Bake for 15 minutes until the edges are brown and golden. Sprinkle over the rocket and pinenuts.