This oven baked 3-ingredient potato and pea casserole is the kind of humble, church-basement classic that disappears from the potluck table before you’ve had time to set down your serving spoon. My sister-in-law first brought it to a church potluck, and people kept circling back for seconds because it tastes like comfort food but doesn’t feel heavy. It leans on a Midwestern staple—canned cream of mushroom soup—to bind together tender roasted potatoes and sweet green peas into a creamy, cozy bake. With just three ingredients and a standard glass baking dish, it’s a practical weeknight side or a fuss-free dish to tote to any gathering.
Serve this casserole hot, straight from the glass baking dish, with something that brings a bit of texture and protein to the plate—roast chicken, baked ham, meatloaf, or simple pan-seared pork chops all work beautifully. A crisp green salad with a tangy vinaigrette or a tray of roasted carrots and onions balances the creaminess. For potlucks, I like to park it next to a basket of crusty bread or dinner rolls so people can scoop up every last bit of the sauce.
Oven-Baked 3-Ingredient Potato and Pea CasseroleServings: 6
Ingredients
2 pounds russet or Yukon Gold potatoes, scrubbed and cut into 1/2-inch cubes
2 cups frozen green peas (no need to thaw)
2 cans (10.5 ounces each) condensed cream of mushroom soup
Directions
Preheat your oven to 375°F (190°C). Lightly grease a 9x13-inch glass baking dish with a thin film of oil or nonstick spray so the potatoes don’t stick.
Spread the cubed potatoes evenly in the bottom of the glass baking dish, making sure they’re in a mostly single layer so they cook at the same rate.
Scatter the frozen peas evenly over the potatoes. Because the peas are small and cook quickly, you want them distributed throughout so every scoop has a good mix of peas and potatoes.
In a medium bowl, whisk or stir the condensed cream of mushroom soup until smooth. You want to loosen it up slightly so it’s easier to spread; if it’s very thick, you can stir it vigorously for 30 seconds to soften.
Pour the cream of mushroom soup over the potatoes and peas. Use the back of a spoon or a spatula to gently spread it so it coats everything as evenly as possible, nudging it into the corners of the baking dish. Do not add extra liquid; the potatoes will release moisture as they bake and the soup will thin into a sauce.
Cover the baking dish tightly with aluminum foil. Bake, covered, for 40 minutes, until the potatoes are starting to turn tender when pierced with the tip of a knife.
Remove the foil, give the casserole a gentle stir to bring some of the sauce up and over the potatoes and peas, and smooth the top again. Return the dish to the oven, uncovered, and bake for another 20–25 minutes, or until the potatoes are fully tender, the peas are bright green, and the top looks lightly golden and bubbly around the edges.
Let the casserole rest for 5–10 minutes after it comes out of the oven. This brief rest allows the sauce to thicken slightly so it clings to the potatoes and peas instead of running when you scoop. Serve warm directly from the glass baking dish.
Variations & Tips
Because this recipe is intentionally just three ingredients, any additions are optional and best reserved for when you’re not trying to stick to the potluck story. If you want a bit more savoriness, you can sprinkle the top lightly with black pepper or paprika before baking without changing the core recipe. For a slightly looser, saucier casserole, stir 1/4 cup milk or cream into the condensed soup before spreading it over the vegetables. To lean into a more Sunday-supper feel, fold in 1–1 1/2 cups of cooked, diced ham or rotisserie chicken along with the peas (this will technically add a fourth ingredient but makes it a full one-dish meal). A handful of shredded cheddar or Parmesan over the top for the last 10 minutes of baking adds a gratinéed finish. If you’re cooking ahead for a potluck, assemble the casserole up to a day in advance, cover, and refrigerate; plan to add 5–10 minutes to the covered baking time to account for the cold dish. Leftovers reheat well in the oven at 350°F, covered, until warmed through, and can be turned into a quick breakfast by topping a warmed portion with a fried or poached egg.
