Cook the noodles just until al dente, according to package instructions.

Sauté the veggies: Melt 1 tablespoon butter in a large skillet. Add celery, onion, peas and garlic and sauté for a few minutes. Set aside.

Make Sauce: Add remaining 3 tablespoons butter to the pan. Once melted, add the flour and cook, stirring, for 1 minute. Slowly whisk in the chicken broth and milk until smooth. Bring to a simmer and stir constantly, until slightly thickened. Reduce heat to low and add salt, dill, lemon juice, parsley, and 1/2 cup parmesan cheese. Taste and add additional seasoning, if needed.

Combine: Remove from heat and stir in the pasta, vegetables and tuna. Pour mixture into a 9x13’’ or similar size baking dish. Sprinkle with remaining 1/2 cup of parmesan cheese.

Add Topping: Crush ritz crackers and add melted butter. Sprinkle mixture over the casserole.

Bake at 350 for 25-30 minutes. Store leftovers in the refrigerator for up to 5 days.