In a bowl, dissolve the yeast in water. Add the oil, salt and 2 types of flour (reserve some of the flour for later). Beat all the ingredients for the dough with a large spoon. Let the dough rise covered, in the refrigerator for at least 8 hours – ideally for 24 hours.
Fill a chimney starter with briquettes and light it. Arrange the hot briquettes around the edge of the (circular) barbecue. Then place the pizza stone on the barbecue grate. Cover the barbecue and let it heat up for 10-15 min. until the stone is very hot.
Tip the dough out onto a floured surface and knead thoroughly. Add the rest of the flour as needed. Roll the dough out into 2 round pizzas (approx. 35 cm in diameter). Place them on baking parchment cut to the exact size of the pizzas. Spread tomato sauce on the 2 bases. Sprinkle the cheese on top, in little flat piles, if you prefer. Bake one pizza at a time on the hot stone – approx. 6 min. – until the crust is golden and crispy.
Meanwhile, combine the drained prawns with the rest of the ingredients, cover and refrigerate for about 15 min.Season to taste. Sprinkle the garlic-marinated prawns over the pizzas, garnish with basil and serve immediately.
You can bake the pizzas in the oven. Place 2 baking sheets in the oven and pre-heat to approx. 250°C – fan setting. Place the pizza bases on 2 pieces of baking parchment. Slide them onto the hot baking sheets and pre-bake on the top and bottom racks for approx. 10 min., or until golden. Remove from the oven and spread them with tomato and cheese. Continuing baking the pizzas for 6-8 min. until the cheese is golden and the crusts are crispy.