Olive Oil: I like using extra virgin olive oil for its flavor, but feel free to use other types of vegetable oil instead (such as sunflower oil, corn oil, avocado oil, etc).

Onion: I used a yellow onion, but you can also use white onions or red onions if you prefer.

Celery: I like the crunchiness and taste that comes from celery, but if you’re not keen on celery you can leave it out.

Pasta: Make sure that the pasta is cooked before assembling the casserole. I used gluten-free rotini pasta, but any type of short gluten-free noodles will work too. If you are not Celiac or gluten-intolerant, feel free to use normal pasta instead.

Tuna: Make sure to drain the tuna of the liquids from the can before using.

Cheddar Cheese: I used dairy-free cheddar cheese to keep this recipe dairy-free. Alternatively, if you are not lactose-intolerant, feel free to use normal cheddar cheese instead.

Ground Paprika: I like to add a bit of ground paprika for a kick of heat. Alternatively, you may also use red chili powder, cayenne powder, or crushed red pepper flakes.

Granulated Garlic: I’m a big fan of garlic, so the recipe wouldn’t be complete with a least a bit of granulated garlic.

Ground Black Pepper: I’ve added ground black pepper for extra spice. Feel free to leave it out or reduce the amount if you don’t want so much heat.

Rosemary: Adding dried rosemary adds more flavor to the casserole. You can also add dried oregano or dried parsley if you prefer.

Green Peas: You can use either fresh, canned or frozen green peas. If using frozen, run the green peas under warm tap water to defrost them before using.

Cream of Mushroom Soup: I used a gluten-free and dairy-free cream of mushroom soup to keep this recipe gluten-free and dairy-free. If you are not Celiac or gluten or lactose intolerant, feel free to use normal cream of mushroom soup.

Panko Breadcrumbs: I used plain gluten-free panko breadcrumbs to keep this tuna casserole gluten-free. If you are not Celiac or gluten-intolerant, go ahead and use normal panko or normal breadcrumbs instead.

Garnishing: I like having a pop of green on top of the tuna casserole for contrast in color. You can either use sliced green onions or chopped fresh parsley for garnishing.

Storing/Freezing: To store, cover the cooled tuna casserole with plastic wrap or place the casserole in an airtight container and store in the refrigerator for up to 4 days. Reheat in the oven or microwave before eating. To freeze, place the casserole in an airtight container and freeze for up to 2 months. Let frozen casserole thaw in the refrigerator overnight before reheating in the oven or microwave and eating.