- 1 pound hollow cavatappi, elbows with lines or macaroni with lines
- EVOO Extra Virgin Olive Oil, for drizzling plus about 3 tablespoons
- 12 ounces line-caught canned tuna, drained (such as salt-free American sustainable canned tuna from Lobster Place)
- 1/2 cup finely chopped herbs such as dill, parsley and tarragon
- 1/2 cup finely chopped red onion or scallions, whites and greens
- 1 to 2 small ribs celery, finely chopped
- Juice of 1 lemon
- 2 tablespoons Dijon mustard
- 1 stick butter, divided
- 3 tablespoons flour
- About 2 1/2 cups whole milk
- 2 cups grated white cheddar or Gruyre
- 1 cup grated Parm cheese
- 1 1/2 cups homemade or panko breadcrumbs
Bring a large pot of water to a boil for the pasta. Salt water and cook pasta to less than al dente, 5-6 minutes. Drain and drizzle with a touch of oil to keep pasta loose.
In a large bowl, flake tuna and add herbs (reserving a tablespoon or 2 to mix with the breadcrumbs). Add onions and celery; dress with lemon juice and 3 tablespoons EVOO and Dijon mustard. Season with salt and pepper to taste. Add pasta and combine well, transfer to baking dish or large casserole.
In a medium saucepot, melt 4 tablespoons butter. Whisk in the flour, cook 1 minute then whisk in milk and season with salt and pepper. Thicken to coat a spoon, stir in cheddar or Gruyre and half the Parm cheese in figure-8 motion. Pour sauce evenly over the pasta and the tuna, and gently combine with a spoon to settle the sauce. Cool and chill for make-ahead meal.
Melt remaining butter in a small pan, add breadcrumbs and reserved herbs. Toss to evenly distribute the butter, remove from heat and transfer to airtight container.
To prepare, bring casserole to room temperature and preheat oven to 400F. Top casserole with breadcrumbs and remaining Parm, and bake until golden and hot through.