Classic Diner Spaghetti Napolitan is a beloved Japanese comfort food inspired by Western-style diner cooking. This nostalgic pasta dish features tender spaghetti tossed in a rich, slightly sweet tomato-ketchup sauce with sautéed onions, bell peppers, and savory sausage or ham. Simple, affordable, and incredibly satisfying, Spaghetti Napolitan is a staple in Japanese cafés, home kitchens, and retro diners.
This recipe is perfect when you want a quick dinner, an easy pasta recipe, or a family-friendly meal made with pantry staples. Its unique flavor comes from ketchup-based sauce balanced with butter and Worcestershire sauce, creating a comforting, umami-rich dish that both kids and adults love.
Ingredients
Spaghetti – 12 oz (340 g)
Olive oil or butter – 1 tablespoon
Onion, thinly sliced – 1 medium
Green bell pepper, thinly sliced – 1
Sausage or ham, sliced – 6 oz (170 g)
Garlic, minced – 1 clove
Tomato ketchup – ½ cup
Worcestershire sauce – 1 tablespoon
Sugar – 1 teaspoon
Salt – ½ teaspoon
Black pepper – ½ teaspoon
Butter – 1 tablespoon
Optional garnish: grated Parmesan cheese or chopped parsley
Instructions
Cook the spaghetti
Bring a large pot of salted water to a boil. Cook the spaghetti according to package instructions until al dente. Drain well and set aside.
Sauté the vegetables and meat
Heat olive oil or butter in a large skillet over medium heat. Add the sliced onion and cook for 2–3 minutes until softened. Add the bell pepper and sausage or ham, and cook for another 3–4 minutes until lightly browned and fragrant.
Add garlic and sauce
Stir in the minced garlic and cook for 30 seconds. Reduce heat to medium-low, then add ketchup, Worcestershire sauce, sugar, salt, and black pepper. Stir well and simmer for 2–3 minutes to mellow the acidity of the ketchup.
Combine pasta and sauce
Add the cooked spaghetti directly to the skillet. Toss gently until the noodles are fully coated in the sauce. Add the butter and continue tossing until melted and glossy.
Taste and adjust
Taste and adjust seasoning with more salt, pepper, or ketchup if needed. Cook for an additional 1–2 minutes to allow the flavors to fully blend.
Serving Suggestions
Serve Classic Diner Spaghetti Napolitan hot, topped with grated Parmesan cheese if desired. It pairs well with a simple green salad, garlic bread, or a fried egg on top for a traditional Japanese café-style presentation.
Storage Tips
Store leftovers in an airtight container in the refrigerator for up to 2 days. Reheat gently in a skillet or microwave, adding a splash of water if needed to loosen the sauce.
Final Thoughts
Classic Diner Spaghetti Napolitan is an easy pasta recipe that delivers big comfort with minimal ingredients. With its nostalgic diner-style flavor, quick preparation, and budget-friendly ingredients, it’s a must-try dish for anyone who loves classic comfort food, simple weeknight dinners, or Japanese-inspired home cooking.
