Grate the medium onion and the four medium potatoes into a large mixing bowl, letting the mixture sit for a few minutes, then press into a clean cloth to drain excess liquid.

In the bowl with the grated vegetables, add three fresh eggs, four tablespoons of all-purpose flour, sea salt, and freshly ground black pepper. Mix thoroughly until all ingredients are well combined.

Heat a non-stick frying pan over medium heat and add a couple of tablespoons of olive oil, allowing it to heat until it shimmers.

Drop dollops of the batter into the hot pan, cooking for approximately 2-3 minutes per side, until golden brown.

Transfer the pancakes to a plate lined with paper towels to drain excess oil.

Preheat your oven to 200°C (400°F) for finishing cooking the pancakes.

In a mixing bowl, combine diced tomatoes, half of the shredded mozzarella cheese, and the chopped fresh dill. Stir gently to mix.

Place fried pancakes on a baking sheet, top with the tomato-cheese filling, and add the remaining mozzarella cheese. Bake for about 15 minutes until the cheese is bubbly.

Let the pancakes cool for a moment, then serve warm with an additional sprinkle of fresh dill.