Dissolve the yeast and sugar in a glass of tepid water. Mix the flour, salt and olive oil in a large bowl, then add the dissolved yeast and enough extra water to bring everything together into a soft dough (usually another 200ml). Knead until smooth. Transfer to a lightly oiled bowl, cover with a cloth or clingfilm, then leave in a warm spot for 2 hours, or until doubled in size.
Lightly oil a 29cm-round tin. Halve the dough. Roll out both pieces on a lightly floured surface – one should be larger than the tin, the other the size of the tin. Press the big piece into it, making sure it comes up the sides. Rub the dough with oil. Arrange the cheese and anchovies, if using, evenly on the dough, sprinkle with a little salt and pepper. Brush the edges with oil, then cover with the remaining dough. Pinch and twist the edges closed. Brush with either oil mixed with water or beaten egg. Poke a few holes in the top with a fork and bake in a preheated oven at 200°C for 25-35 minutes, or until golden and puffed up.