Slow-Cooker Seafood Fra Diavolo Linguine Step-by-step instructions

Before you start

Before you start, make sure your slow cooker is clean and dry. Mince the garlic, measure out the chili flakes, oregano, and olive oil, and have the crushed tomatoes and red wine ready. Clean the mussels: scrub the shells under cold running water and pull off the fibrous beards.

Peel and devein the shrimp if needed, and pat all seafood dry. Keep the seafood refrigerated until you're ready to add it. Measure the linguine and set it aside — it will be added later. Have a wooden spoon and an instant-read thermometer on hand.

Instructions

Build the Sauce Base

1. 1Build the Spicy Sauce Base
   In the slow cooker, combine the crushed San Marzano tomatoes, dry red wine, minced garlic, Calabrian chili flakes, dried oregano, and olive oil. Stir everything together until the garlic and chili flakes are evenly distributed throughout the sauce.
   Look for The sauce should be a deep red with flecks of chili and garlic.
   Tip Use a wooden spoon to scrape the bottom of the slow cooker to ensure nothing sticks.
2. 2Cook the Sauce Low and Slow
   Cover the slow cooker and cook the sauce on LOW for 3 hours. The sauce will thicken slightly and the flavors will meld together.
   Look for The sauce should be simmering gently and smell richly of tomatoes and garlic.
   Tip Resist the urge to lift the lid often — the heat escapes and slows cooking.

At the end of this phase, the sauce should be a rich, deep red with visible flecks of chili and garlic. The aroma should be intensely tomatoey, with a hint of wine and a spicy undertone. The sauce will look slightly thickened and the oil may have risen to the surface — that's fine. Give it a quick stir before adding the seafood.

Cook the Seafood and Pasta

3. 3Add the Seafood and Pasta
   After 3 hours, stir in the shrimp, calamari rings, mussels, and linguine, making sure the pasta is submerged in the sauce as much as possible. Cover and cook on LOW for 15 minutes.
   Look for The pasta will soften and the seafood will begin to turn opaque.
   Safe temperature 145°F (63°C) internal temperature (shellfish)
   Tip If the pasta isn't fully submerged, gently push it down with a spoon.
4. 4Check Seafood Doneness
   After 15 minutes, check that the shrimp are pink and opaque, the calamari rings are tender, and the mussels have opened. The internal temperature of the seafood should reach 145°F (63°C). Discard any mussels that remain closed.
   Look for Shrimp are curled and pink, calamari is firm but tender, mussels have opened.
   Safe temperature 145°F (63°C) internal temperature (shellfish)
   Tip Use an instant-read thermometer to verify the temperature.

After this phase, the shrimp should be pink and curled, the calamari rings opaque and tender, and the mussels opened. The linguine will have absorbed some sauce and should be al dente.

The sauce will have thinned slightly from the liquid released by the seafood and pasta, but should still cling to the noodles. The whole pot will smell wonderfully of garlic and the sea.

Serve and Garnish

5. 5Serve the Pasta
   Twirl the linguine and seafood onto serving plates or a large platter. Garnish with fresh parsley and serve with lemon wedges on the side.
   Look for The pasta is coated in the spicy red sauce, with seafood nestled throughout.
   Tip Squeeze fresh lemon over the top just before eating to brighten the flavors.

The final dish should look vibrant: crimson sauce coating the linguine, with pink shrimp, white calamari rings, and glossy mussels scattered throughout. The parsley adds a fresh green contrast, and the lemon wedges offer a bright, citrusy note when squeezed over the top. The texture should be saucy but not soupy, and every bite should have a pleasant heat.

Common mistakes

One common mistake is overcooking the seafood, which makes it rubbery. Stick to the 15-minute cook time and check early. Another is using a slow cooker that's too small — if everything doesn't fit, the pasta won't cook evenly.

Also, don't lift the lid during the initial 3-hour simmer, as this releases heat and extends cooking time. Finally, be careful with the chili flakes: Calabrian chilies are spicy, so adjust the amount to your heat tolerance. If you prefer a milder dish, start with less and add more at the end.

How to tell it’s done

The dish is done when the shrimp are pink and opaque, the calamari rings are firm but tender, and the mussels have opened wide. The linguine should be al dente — tender but with a slight bite. The sauce should be thick enough to coat the pasta, not watery.

Insert an instant-read thermometer into the thickest part of the shrimp or a calamari ring; it should read at least 145°F (63°C). Discard any mussels that haven't opened. Let the dish rest for a couple of minutes before serving to allow the flavors to settle.

• Shellfish: 145°F (63°C) in the thickest part