Step 1
Beat eggs and salt lightly in a bowl.
Step 2
Stir 1/2 cup plus 2 1/2 tablespoons lukewarm milk yeast and sugar together in a bowl. Let stand until foamy about 5 minutes.
Step 3
Mix tipo 00 and bread flours together in a bowl. Make a well in the center. Add beaten eggs and yeast mixture. Mix together with a fork. Add water and mix again to form a sticky ball. Knead butter into the dough a little bit at a time.
Step 4
Transfer dough to a floured work surface and knead vigorously until smooth about 10 minutes. Place in a lightly floured bowl cover with a clean damp cloth and let rest in a warm place until doubled in volume about 1 1/2 hours.
Step 5
Turn dough out on a floured surface. Stretch out one piece and fold it over the top. Repeat with another section of dough working your way around the circle. Place dough in a paper panettone mold. Cover with plastic wrap and let rise in a warm place until dough reaches the rim of the mold about 2 hours.
Step 6
Preheat oven to 350 degrees F (175 degrees C). Fill a baking dish with some water and place it on the bottom rack of the oven to keep the panettone moist as it bakes.
Step 7
Brush the top of the panettone with some milk and place the mold on a flat baking sheet.
Step 8
Bake in the preheated oven until a skewer inserted into the middle comes out clean 40 to 45 minutes. Allow to cool on a wire rack for a few minutes. Pierce the side near the bottom with 2 long wooden skewers that will stick out the other side. Flip the panettone gently and set the skewers on the rim of a tall pot. Cool panettone upside down so it doesn't collapse at least 5 hours.
Step 9
Mix tuna and mayonnaise together in a bowl until smooth. Blend olives olive oil anchovy fillets and capers in another bowl until smooth. Mix cream cheese and ham together in a third bowl.
Step 9
Remove skewers gently from the panettone and slice lengthwise to obtain 6 slices including the top. Lay the bottom slice on a serving plate; spread with tuna mixture. Cover with shrimp and lettuce. Press second slice on top; add third slice. Spread olive mixture on top and cover with mozzarella cheese. Press fourth slice on top; add fifth slice. Spread cream cheese mixture on top and cover with prosciutto. Cover with the top slice.