Dissolve the shiitake mushroom powder, chicken stock, dry yeast and sugar in the water. Mix in the flour and finally work the olive oil into the dough. Knead until you have a smooth, slightly shiny dough. Let rise in a warm place for 1 hour. Knead briefly, roll out to a diameter of 28 cm and place in a greased 32 mm pan.
Using a fork, perforate the base a little and cover and let rise for another 30 minutes. Fry over moderate heat until the underside of the base has light brown spots. Remove from heat and flip the bottom.
In the meantime, wash the small, red chilli, cut diagonally into thin rings, leave the grains and discard the stem. Squeeze the garlic cloves and mix them with the chilli and tomato ketchup into the pesto.
Cap the small, red onions at both ends, peel and cut across into slices approx. 2 mm thick. Wash the tomatoes, remove the stems and cut across into 8 mm thick slices. Wash the peppers, cut the stem, cut in half lengthways, core and halve the halves lengthways.
Rinse the anchovy fillets well and cut across into pieces approx. 1 cm long. Strain the tuna, have the oil ready and, if necessary, cut the meat into large pieces. Finely chop the olives and coarsely grate the pecorino.
Spread a thin layer of the pesto on the browned side and sprinkle with 30 g of pecorino cheese. Place the tomato slices, the pepper strips and the tuna pieces. Spread the anchovy and olive pieces over the top. Sprinkle with the herb mix, cover with the remaining pecorino cheese and finish with the oil from the tuna can drizzled over everything.
Baked in the oven at 250 degrees top heat until the pecorino has melted. The melted cheese should not have any brown spots, as these have a slightly bitter taste. Take out of the oven, cut into 8 parts on a wooden board, serve warm and enjoy as finger food.