In a pan, put some olive oil and add chopped shallot, capers, anchovies in oil, and tuna in oil.

Cook over medium heat until the ingredients have softened.

Add the flour and mix well to form a cream.

Gradually pour the milk into the pan, stirring constantly to avoid lumps from forming.

Cook the sauce over medium-low heat until it thickens slightly.

In the meantime, cook the conchiglioni pasta in salted water until al dente.

Drain the pasta and stuff it with the previously prepared tuna cream.

Arrange the stuffed conchiglioni in a lightly greased baking dish.

Bake the conchiglioni at 180°C for 3-4 minutes, until the surface is golden brown.

While the conchiglioni are in the oven, prepare the diced tomato dressing.

In a pan, heat some olive oil and add the chopped garlic.

Add the diced tomatoes and sauté for a few minutes.

Add the basil leaves and mix well.

Serve the stuffed conchiglioni hot, accompanied by the diced tomato dressing.