Bring a large pot of water to boil for the pasta. Salt the water and cook the pasta to less than al dente
, 5 to 6 minutes. Drain
with a touch of oil to keep the pasta
In a large bowl, flake the tuna and add the herbs
(reserving a tablespoon or 2 for breadcrumbs), onions
, mustard, celery, lemon juice
, EVOO and some salt and pepper. Add the pasta and combine well. Transfer to a baking dish
or large casserole dish
In a medium saucepot, melt
4 tablespoons of butter. Whisk
in the flour and cook 1 minute. Then whisk in the milk and season with salt and pepper, thicken to coat the back of a spoon. Stir in the Cheddar in a figure-eight motion. Pour the sauce evenly over the pasta and tuna. Gently combine with a spoon to settle the sauce
. Cool and store for a make-ahead meal.
Melt the remaining 4 tablespoons of butter in a small pan and add the breadcrumbs and reserved herbs, toss to evenly distribute the butter
, remove from heat and transfer to airtight container.
To prepare, preheat the oven to 400 degrees F and bring the casserole to room temperature. Top the casserole with breadcrumbs
and Parm cheese. Bake until golden and hot through.