Ingredients :

• Canned tuna in water — Always in water, not in oil. Tuna in oil will release fat into the mixture and unbalance the texture. Two 150 g drained cans are more practical than looking for a single 300 g format. Flake it with a fork — coarsely, not into a mush — so you still find pieces to bite into.
• 0% Fat Fromage Blanc — This is what replaces cream and heavy béchamel sauces. The 0% version gives a melting texture very close to crème fraîche once cooked, without any yogurt taste. Avoid ‘faisselle’ (curd cheese), which is too liquid. Take the classic pot version and beat it well with the eggs before incorporating the rest.
• Bell Peppers — Red, yellow, orange — any color works, but avoid green which stays bitter after cooking. The key is to sauté them beforehand: raw in the gratin, they will release too much water and soak the whole mixture. Three to five minutes in a hot pan, and the problem is solved.
• Black Olives — They provide texture and a briny note that contrasts with the sweetness of the rest. Choose pitted marinated olives rather than basic brine ones if you want a bolder taste. Cut them coarsely — into two or three pieces — so they are present without dominating.