3: Remove the sardines from the tins and cut into small pieces (you can remove the bones and tails if you prefer). Set aside.
4: Cut 800 g cooked potatoes into medium-sized pieces.
5: Brown them to taste in a large frying pan in a little oil, adding salt at the end. Set aside.
6: In the same pan, pour 3 tablespoons of oil, and when hot, add the shallots. Season with salt and pepper, and cook for 1 minute, stirring constantly. Set aside.
7:
Assembling the gratin
Preheat oven to 200°C (390°F). Pour half the potatoes into a buttered gratin dish.
8: Pour over the cooked shallots.
9: Then the sardines.
10: Chopped parsley.
11: And finally, the other half of the potatoes.
12: Pour in the egg mixture, then sprinkle with 50 g grated cheese.
13: Bake at 200°C (390°F) for approximately 30 minutes.
Remarks
You can replace sardines in oil with other fish, fresh, smoked or canned too.