From Coastal Living magazine October 2010. My sister made this for a baby shower we attended this weekend and the response was overwhelming - EVERYONE - including the mama-to-be, wanted this recipe!! We never grew up with tuna casserole (our mother is from Spain), but for a first time try, this one was out of the park. Definitely nice enough for company, and easy to make! The only changes she made were to add a few grinds of black pepper and she subbed one of the cans of oil-packed tuna for a water-packed one as she had it in her pantry already. Although I think that the mild flavor of the leeks was one of the keys, I'm sure subbing regular sauteed onions would be acceptable. Don't skimp on the Gruyere; she added a bit extra there too :)