I use a full teaspoon of onion powder in this recipe for added flavor, but not everyone likes that much onion flavor, so the recipe says 1/2 to 1 teaspoon. If you aren't a fan of peas, you can substitute an equal sized drained can of any other vegetable that you like in place of the peas in this recipe. You can also substitute canned chicken for the tuna. You can top the finished dish with some shredded cheese and cover it for a few minutes on the stove to allow the cheese to melt. It's easy to turn this into a casserole, simple put the prepared recipe into a casserole dish and top with some shredded cheese and heat in the oven until the cheese is melted.