Preheat the oven to 180°C / 350°F and line the baking sheet with baking paper.

Slice the yellow onion into thick slices.

Heat 1 tablespoon olive oil in the frying pan and sauté the yellow onion for 3 to 5 minutes until lightly grilled but still firm.

Combine the all-purpose flour, water, 30 g Parmesan cheese, remaining olive oil, and salt in a mixing bowl.

Fold the lightly grilled yellow onion into the flour batter until evenly coated.

Pour the onion batter onto the lined baking sheet and spread it into a thin, even layer with the spatula.

Grate the remaining 20 g Parmesan cheese evenly over the top of the batter.

Bake the scarpaccia for 30 minutes at 180°C / 350°F until golden and crisp around the edges.

Let the baked scarpaccia cool for 5 minutes until warm enough to handle.

Halve the cherry tomato and chop the sun-dried tomato, spring onion, and fresh basil.

Toss the tomatoes, spring onion, basil, fleur de sel, and 1 tablespoon olive oil in a clean mixing bowl.

Cut the warm onion scarpaccia into 4 portions and top each portion with burrata and tomato salad.