One-Pan Roasted Tomato Pepper Pasta Step-by-step instructions

Before you start

Heat the oven to 425°F (220°C) and set a large oven-safe skillet or Dutch oven on the stovetop. Have all the vegetables prepped: tomatoes whole, peppers stemmed and seeded, onion sliced, garlic peeled.

Measure the olive oil, salt, and oregano. Bring a kettle or pot of water to a boil so you have 2 cups of boiling water ready when needed. Shred the mozzarella if not already shredded.

Instructions

Roast and Smash

1. 1Roast the vegetables
   Heat the oven to 425°F (220°C). In a large oven-safe skillet or Dutch oven, combine the whole plum tomatoes, red peppers, sliced onion, and garlic cloves. Drizzle with the olive oil, sprinkle with the salt and oregano, and toss to coat everything evenly. Arrange the vegetables in a single layer, cut-side down if any tomatoes are very large. Roast for 20 to 25 minutes, until the tomato skins are blistered and charred in spots and the peppers are softened and sweet.
   Look for The tomatoes look collapsed and charred at the edges; the peppers are tender and the onions are translucent.
   Tip Use a pan that can go from oven to stovetop to keep this a true one-pan dish.
2. 2Smashed the roasted vegetables
   Remove the skillet from the oven and set it on a heatproof surface. Using a potato masher, crush the roasted tomatoes, peppers, onions, and garlic right in the pan until you have a chunky, saucy mixture. Stir in 1/2 cup of the boiling water to loosen the sauce and scrape up any browned bits from the bottom of the pan. The sauce should be thick but pourable; add another 1/4 cup of water if needed.
   Look for The vegetables break down easily into a rustic, jammy sauce with small chunks remaining.
   Tip Don't over-mash — leaving some texture adds interest and helps the pasta hold the sauce.

After roasting, the tomatoes should look collapsed and charred in spots, the peppers soft, and the onions translucent. The kitchen will smell sweet and slightly smoky.

Smash the vegetables with a potato masher until you have a chunky sauce. The mixture should be thick and jammy, with no large pieces remaining.

Simmer and Melt

3. 3Add the pasta and water
   Place the skillet over medium-high heat. Add the dry conchiglie pasta and the remaining 1 1/2 cups boiling water. Stir well to combine, making sure the pasta is mostly submerged in the sauce. Bring the mixture to a simmer, then reduce the heat to medium-low. Cover the skillet with a lid or foil and cook, stirring occasionally, for 12 to 15 minutes, until the pasta is al dente and has absorbed most of the liquid.
   Look for The sauce bubbles gently and the pasta shells are tender but still hold their shape.
   Tip Stir every few minutes to prevent sticking; add a splash of hot water if the pan looks dry before the pasta is done.
4. 4Fold in the mozzarella
   Once the pasta is cooked, remove the skillet from the heat. Sprinkle the shredded mozzarella over the pasta and gently fold it in with a wooden spoon until the cheese is melted and creamy. The sauce will become glossy and slightly stringy. If the mixture seems too thick, stir in a tablespoon or two of hot water to loosen it to a creamy consistency.
   Look for The cheese pulls into long strands as you fold, and the sauce turns silky and rich.
   Tip Fold rather than stir vigorously so the shells stay intact and the cheese doesn't clump.

The pasta should be tender but still hold its shape, and the sauce should be thick and creamy. The mozzarella should be fully melted and glossy, with no visible clumps. The dish should look like a hearty, rustic pasta with a rosy-orange sauce. The aroma will be rich and cheesy.

Finish and Serve

5. 5Serve with parsley and pepper
   Spoon the pasta into warm bowls. Top each serving with a generous sprinkle of chopped fresh parsley and a few turns of freshly ground black pepper. Serve immediately while the cheese is still stretchy and the sauce is piping hot.
   Look for The pasta is coated in a creamy, rosy sauce with visible bits of pepper and charred tomato.
   Tip For extra richness, drizzle with a little olive oil just before serving.

The pasta should be piping hot, with the cheese stretchy and the sauce clinging to each shell. The parsley adds a fresh green contrast, and the black pepper gives a subtle kick. The dish is ready to serve immediately, with the sauce still bubbling slightly.

Common mistakes

One common mistake is not roasting the vegetables long enough; they need to be blistered and softened to release their sweetness. Another is adding too much water, which makes the sauce thin and watery.

Stir the pasta occasionally while it simmers to prevent sticking. Finally, don't add the cheese too early or it can become stringy and tough.

How to tell it’s done

The pasta is done when it is al dente, meaning tender but still slightly firm to the bite. The sauce should be thick and creamy, coating the shells without being watery.

The mozzarella should be fully melted and stretchy when you lift a spoonful. If the sauce seems too loose, simmer uncovered for a few more minutes; if too thick, add a splash of hot water.