Rinse the zucchetti and cut lengthwise slightly diagonally into slices. Also rinse the mushrooms, twist out the stems, chop and season, set aside.
Marinate the zucchini slices and mushroom heads with the olive oil and spices for 1/2 hour. Preheat oven to 220 degrees.
Briefly sauté the chopped mushroom stems together with the onions and the Bel Paese in a pan, stirring well until a homogeneous, relatively compact quantity is obtained. Fill this into the mushroom heads.
Put the mushrooms and the zucchini slices in a baking dish and cook them in the oven for 10-15 minutes.
Slice the tomatoes diagonally to the stem (this will give more “spokes” to hold the flesh together better).
Chop the basil. Cut the mozarella into slices as well.
Marinate both with pepper, sprinkle seasoning, garlic powder or salt, oil and the basil and arrange in alternating bricks.
For the crostinis, cut the baguettes diagonally into slices about 1 1/2 cm thick. Preheat oven to 220 °C.
For the first topping, pit the olives. Grind half of the green and black olives with a cutter or possibly a hand blender, chop the remaining olives, mix with the olive puree, squeeze the garlic and add.
For the second topping, roughly chop the tomatoes and grind them together with the pine nuts and the Parmesan cheese in a cutter or possibly with a hand blender.
Sprinkle the slices of bread with olive or tomato oil.