Heat a pot of water to boil for egg noodles. Preheat oven to 400F.
In small skillet, melt 4 tablespoons butter. Pour into a small bowl and combine with panko, cheese and parsley. Reserve.
Heat 1 tablespoon EVOO, a turn of the pan, and remaining 3 tablespoons butter in a skillet over medium to medium-high heat. Add mushrooms and saut to tender, 6-7 minutes. Add shallots, garlic, thyme, salt and pepper, and stir 2-3 minutes more. Sprinkle in flour and stir a minute more, whisk in wine then half-n-half. Bring sauce to a bubble then reduce heat and thicken to coat the back of a spoon. Stir in Dijon and tarragon.
While the sauce thickens, cook the egg noodles to al dente.
Combine flaked tuna with sauce. Drain egg noodles and return to hot pot. Pour in tuna and sauce, and stir to combine. Transfer to baking dish and top with breadcrumb topping. Bake to golden, 15 minutes.