This slow cooker 4-ingredient tuna noodle casserole is my Aunt Sheila’s exact kind of retro comfort food—creamy, thrifty, and perfect for meatless Fridays. It leans into the classic Midwestern pantry formula: canned tuna, condensed cream of mushroom soup, peas, and curly egg noodles. Everything simmers low and slow right in the crock, so you get those tender noodles and flaky tuna in a velvety sauce without turning on the oven. It’s the sort of dish many of us grew up with, just adapted to the slow cooker for busy modern kitchens.
Serve this casserole straight from the slow cooker with a simple green salad dressed in a sharp vinaigrette to cut through the richness. Buttered toast, garlic bread, or plain crackers are very much in the spirit of the era and are great for scooping up the creamy sauce. A side of steamed green beans or roasted carrots keeps the plate colorful, and if you enjoy a bit of acidity, a few dill pickle spears or pickled beets on the side add a surprisingly nice contrast.
Slow Cooker Tuna Noodle Casserole
Servings: 6

Ingredients
12 oz dry wide egg noodles (curly style)
2 cans (10.5 oz each) condensed cream of mushroom soup
2 cans (5 oz each) tuna in water, drained and flaked
2 cups frozen green peas (no need to thaw)
3 1/2 cups water
1/2 tsp kosher salt, or to taste
1/2 tsp black pepper, or to taste
Directions
Lightly coat the inside of a 5- to 6-quart slow cooker with nonstick cooking spray to help prevent sticking.
In a large bowl, whisk together the condensed cream of mushroom soup and the water until smooth and evenly combined. Season with the salt and black pepper.
Add the drained, flaked tuna and the frozen peas to the soup mixture and stir gently to distribute everything evenly.
Place the dry egg noodles into the prepared slow cooker. Pour the soup-tuna-pea mixture over the noodles, using a spatula to press down and make sure most of the noodles are submerged in the liquid.
Cover the slow cooker with the lid and cook on LOW for 2 to 2 1/2 hours, stirring once about halfway through if possible to help the noodles cook evenly. The casserole is done when the noodles are tender, the tuna is flaky, and the sauce is creamy and thickened.
Once cooked, give the casserole a final gentle stir to bring up any sauce from the bottom and evenly coat the noodles. Taste and adjust seasoning with a bit more salt and pepper if needed.
Serve warm straight from the slow cooker, making sure each portion has plenty of noodles, tuna, peas, and creamy sauce.
Variations & Tips
To stay true to the four-ingredient spirit, think of the base as tuna, noodles, peas, and cream of mushroom soup; the extra water and seasonings are simply there to make the slow cooker do its job. For a slightly richer version, you can swap 1 cup of the water for whole milk or half-and-half, which will give the sauce a silkier texture without changing the fundamental character of the dish. If you like a bit of crunch but don’t want to fuss with the oven, sprinkle crushed potato chips or buttered breadcrumbs over individual bowls just before serving—very in keeping with its retro roots. You can also play with the shape of the noodles; any curly egg noodle will give you that familiar, cozy texture. If you need to hold the casserole for a bit, switch the slow cooker to WARM and stir in a splash of hot water or milk if it thickens too much. Leftovers reheat well on the stovetop over low heat with a little extra water or milk stirred in to loosen the sauce.