Recipes › Pasta › Onion Pasta Recipe

Onion Pasta Recipe

Recipe by Pedro M. A. Neves

This classic Italian pasta celebrates the humble onion with a silky, caramelized sauce that builds deep, sweet flavor through patient cooking. Cacio e cipolla combines slowly cooked onions with pecorino cheese and pasta water to create a luxurious, naturally creamy dish with minimal ingredients and maximum taste.

Ingredients

• 800 g yellow onions, thinly sliced
• 400 g spaghetti or tonnarelli
• 80 g pecorino romano cheese, finely grated
• 60 ml extra virgin olive oil
• 1 teaspoon sea salt, plus more for pasta water
• ½ teaspoon black pepper
• ¼ teaspoon red pepper flakes (optional)
• Water for pasta

Instructions

1. Bring a large pot of salted water to a rolling boil.

2. While water heats, warm the olive oil in a large, heavy-bottomed skillet over medium-low heat.

3. Add the sliced onions and sea salt to the oil, stirring to coat evenly. Cook uncovered for 35-40 minutes, stirring every 5 minutes, until the onions are deep golden brown and completely soft.

4. When the onions are nearly done caramelizing, add the pasta to the boiling water and cook until al dente, about 9-10 minutes.

5. Reserve 250 ml (1 cup) of pasta cooking water before draining the pasta.

6. Add the hot drained pasta directly to the skillet with the caramelized onions, stirring gently.

7. Remove from heat and add the grated pecorino romano cheese in two batches, stirring constantly and adding pasta water a little at a time until a silky sauce forms. Season with black pepper and red pepper flakes if desired.

8. Divide into serving bowls immediately and top with additional grated pecorino and cracked black pepper.

Substitutions

• Use grana padano instead of pecorino romano for a slightly milder, nuttier flavor
• Substitute shallots for half the onions for a more delicate, refined taste
• Use gluten-free pasta for a gluten-free version, adjusting cooking time as needed
• Replace pecorino with aged asiago for a deeper, more complex cheese flavor

Tips

• Do not rush the onion caramelization—low, slow heat develops the natural sugars that give this dish its character
• Keep the heat off when adding cheese to prevent it from clumping; the residual heat and starchy pasta water will emulsify smoothly
• If the sauce seems too thick, add pasta water one tablespoon at a time rather than all at once
• Serve immediately in warm bowls to maintain the silky texture of the sauce

This Roman pasta, known as cacio e cipolla or onion and cheese pasta, is a humble regional specialty that exemplifies the Italian philosophy of transforming simple ingredients through technique rather than abundance. It reflects the practicality of peasant cooking while delivering sophisticated, complex flavor.

You might also like

Orecchiette With Broccoli Rabe Recipe

30 min · Pasta

Oreo Lasagna Recipe

30 min · Pasta

Paccheri with Tomato Sauce Recipe

50 min · Pasta

Pantry Puttanesca Recipe

30 min · Pasta