In a large bowl, whisk together the flour and water to form a batter.
Add the zucchini, onion, breadcrumbs, rosemary, salt, and pepper. Mix well.
Line a baking sheet with parchment paper. Drizzle with olive oil and sprinkle with semolina.
Spread the batter evenly. Drizzle more olive oil and sprinkle with semolina on top.
Bake at 400°F for 45 minutes, or until crispy and golden.
