Preheat the oven to 475°F (245°C).
Lightly oil a large baking sheet.
Roll out the flatbread dough into a rectangle to fit the pan.
Brush the dough with olive oil.
Spread the pizza sauce evenly over the dough, leaving a ½-inch border.
Sprinkle the shredded mozzarella cheese over the sauce.
Arrange the cauliflower florets evenly across the flatbread.
Bake for 8 minutes, until the cheese begins to melt and the edges start to crisp.
Remove from the oven.
Place the mozzarella ghost cutouts on top of the melted cheese.
Press sliced black olives into the ghosts to create eyes and mouths.
Add whole or halved black olives around the flatbread to look like gravestones.
Return to the oven and bake for 5–7 minutes more, until the ghosts are melted but still hold their shape and the crust is golden brown.
Remove from the oven and let cool slightly.
Sprinkle with fresh parsley or cilantro for garnish.
Slice into squares and serve warm.