Spicy casserole with Adriatic Queen sardines in vegetable oil with pepper and potatoes

1. Peel and cut the potatoes into small pieces, then boil them until soft.
2. In another bowl, whisk the eggs with the yogurt, add salt, pepper, water, olive oil and Parmesan, and mix well.
3. Fry the sliced ​​onion in butter.
4. Add halved cherry tomatoes and sauté briefly.
5. Pour in the tomato concentrate and stir.
6. Add the chopped sardines, season with basil and salt, and simmer briefly until the vegetables are soft.
7. Place a few cubes of butter in the pan.
8. Arrange the boiled potatoes, then the vegetables with the sardines, and pour the egg and yogurt mixture over everything.
9. Bake in the oven at 190 °C for about 20 minutes until the casserole is a nice golden color.