Use a baking tray. Grease tray with oil. Roll out the pastry to fit the tray. Place on tray and preheat oven to 250 degrees C.
For the topping, peel onions and slice into thin rings. Heat oil in a large pan and cook onions over medium heat until transparent and soft. Add the wine and salt and pepper. Spread mixture over dough, leaving an edge 2.5 cm wide.
Slice tomatoes; spread evenly on top of onions. Sprinkle with herbs and cheese. Rinse anchovy fillets, pat dry and slice into 2 or 3 pieces lengthwise. Arrange strips in a diamond pattern over the top of the pissaladière. Place an olive in the centre of the diamonds.
Whisk egg with 1 tablespoon water and brush over edges of the dough. Briefly leave pissaladière to rise in a cool place, then bake for 10–15 minutes. Cut into slices while hot and serve.