Instructions

  1. Set oven to 350 degrees F.
  2. Grease an 11 x 7 or 13 x 9-inch baking dish with cooking spray (or use a casserole dish large enough to hold the mixture).
  3. Boil the pasta in a large pot of boiling water until al dente; drain then transfer to a large bowl.
  4. Add in onion and tuna; toss to combine.
  5. In a saucepan heat soup with milk until smooth.
  6. Stir in mushrooms mayonnaise, Mrs Dash seasoning, garlic powder and black pepper until combined; pour into the bowl and toss to combine.
  7. Transfer mixture to prepared baking dish.
  8. Bake for about 30 minutes.
  9. Remove from oven then sprinkle with cheddar cheese, return to oven for 2-4 minutes to melt the cheese.