Grate the pecorino & set aside.
Chop the mushrooms & set aside.
Chop the ham & set aside.
Mix the canned tomato pulp w/ olive oil, dried oregano, sugar, salt & pepper & set aside.
Slice the mozzarella balls & set aside.
Prepare the pizza pastry along to the description on the packet. (I mixed the ready-to-go flour mix w/ 125 ml warm water using an electric handheld mixer; afterwards just knead the pastry w/ your hands.)
Roll out the pastry to fit in the tart form.
Oil the tart form slightly - if necessary.
Fit the pizza pastry in the tart form & cut off the edges.
Add some olive oil & distribute evenly on top of the pastry.
Add most of the tomato pulp mix.
Add about 2 tbsp grated pecorino.
Add chopped mushrooms & ham.
Add rest of the tomato pulp mix.
Add rest of the grated pecorino.
Cover everything w/ mozzarell slices.
Bake in the oven at 175° C w/ fan for about 35 min. (Check the oven time recommended on the packet of the pizza pastry!)
Serve at once: let the pizza quiche cool down for about 10-15 min; then cut into 4 pieces. (Attention: it's hot & soft & there's liquid ... spilling around ...)
Otherwise: let it cool down to room temperature, cut it into 4 or 8 pieces & serve. (It's more solid then.)