Slice the onions thinly (preferably with a mandolin) and soak in water.
In a bowl, combine the flour and water to form a batter.
Add the onion, breadcrumbs, cheese, rosemary, salt and pepper and mix well.
Line a baking sheet with parchment paper. Drizzle with olive oil and sprinkle with some semolina.
Spread the batter evenly, using your fingers like making focaccia to help spread it. Drizzle with more olive oil and sprinkle more semolina on top.
Bake in a preheated oven at 400°F (200°C) for 45 minutes, and then broil until crispy and golden.
Note: Easy Italian appetizer! This Schiacciata do Cipolle is golden, crispy, and packed with onions. The perfect snack for parties, aperitif, or whenever you’re craving something savory.
