- 2 Tbsp. all-purpose flour
- 1 shallot, finely chopped
- 2 Tbsp. butter (for sauce) + 1 Tbsp. butter (for topping)
- 2 cups milk
- 4 oz Parmesan (for sauce) + 1/4 cup (for topping), coarsely grated
- 1/4 tsp. smoked paprika
- 1 Tbsp. chopped tarragon
- 3 cups medium shells
- 1/2 celery stalk, finely chopped
- 1/2 cup white beans, drained and rinsed
- 1 (5oz) can tuna, drained
- 1/3 cup panko breadcrumbs
- salt and pepper, to taste
- Preheat oven to 350F.
- Over medium heat, melt 2 Tbsp. butter in a heavy skillet. Add shallots and flour, stirring constantly for 3-5 minutes. Slowly add mix and continue to simmer until sauce coats the back of a wooden spoon, ~10 minutes. Turn heat to low, add Parmesan until homogenous.
- Add paprika and tarragon.
- Boil medium shells until al dente. Drain in colander.
- Add shells, celery, beans, and tuna to skillet. Stir to combine. Season with salt and pepper to taste.
- Transfer to an oven safe dish.
- Heat remaining 1 Tbsp. butter until melted. Add breadcrumbs to combine. Remove to a bowl and stir in remaining 1/4 cup Parmesan. Top casserole with breadcrumbs mixture.
- Bake for 25-30 minutes until breadcrumbs are browned and casserole is heated thoroughly.