Kittencal's Tuna-Spaghetti Casserole



  • 8
    ounces spaghetti, pieces (I usually just use a large handful of spaghetti, use the regular not thin or angel hair)
  • 14
    cup butter (can use a little more butter when frying)
  • 12
    lb fresh sliced mushrooms
  • 1
    medium onion, chopped
  • 2
    tablespoons fresh minced garlic (or to taste)
  • 14
    teaspoon cayenne (optional or adjust to taste)
  • 5
    tablespoons all-purpose flour
  • 2 -4
    teaspoons chicken bouillon powder (I just use 1 small package OXO bouillon powder)
  • 2
    cups good-quality chicken broth
  • 1
    cup half-and-half cream (or use 18% table cream)
  • 13
    cup grated parmesan cheese (or use 1-1/2 cups grated cheddar cheese)
  • salt & freshly ground black pepper (to taste, I use seasoned salt)
  • 2
    (170 g) cans tuna (drained and hand-squeezed to remove any moisture)
  • 1
    green bell pepper, seeded and chopped
  • 2
    egg yolks
  • 1
    cup grated cheddar cheese (optional or to taste)


  • Butter a 13 x 9-inch baking dish.
  • Chop the spaghetti coarsely. (I usually chop about 4-inches but it does not have to be exact).
  • Cook the spaghetti until firm-tender (do not overcook the pasta!) drain and toss with 1-2 tablespoons butter or oil to prevent sticking.
  • In a saucepan melt 1/4 cup butter over medium heat (can use a couple tablespoons more butter if desired, I always do!) add in the sliced mushrooms and cook stirring until they release their moisture (about 6 minutes).
  • Add in onion, garlic and cayenne pepper; sauté for about 3 minutes.
  • Add in flour and chicken bouillon powder; mix with a wooden spoon for about 1-2 minutes (the mixture will be slightly "clumpy").
  • Stir in the broth and cream; bring to a light boil over medium heat whisking continuously until smooth and thickened.
  • Turn off heat and stir in the Parmesan cheese (or cheddar cheese if using) mix to combine until melted.
  • Season sauce with salt and black pepper (I use seasoned salt).
  • Add the cooked cream mixture to the cooked spaghetti; toss well to combine, then add in the tuna, green bell pepper and egg yolks; mix very well to combine.
  • Transfer the mixture to a prepared baking dish.
  • Top with additional Parmesan cheese if desired.
  • Bake for 30-35 minutes in a 350°F oven (oven rack set to second-lowest position).
  • If desired you may sprinkle about 1 cup (or more) grated cheddar cheese on top after baking but that is only optional.