Step 1: Caramelize the Onions
In a large skillet over medium-low heat, add olive oil (or butter) and sliced onions. Cook low and slow—about 30–40 minutes—stirring every so often until they’re deeply golden, sweet, and jammy. Add a pinch of salt partway through. Yes, it’s worth the wait.

Step 2: Boil the Pasta
While the onions do their thing, cook your pasta in salted boiling water until al dente. Before draining, scoop out about ½ cup of the starchy pasta water and save it for later.

Step 3: Make the Chili Oil
In a small saucepan, heat olive oil over medium-low heat. Add garlic and cook until it’s just starting to turn golden. Then add red pepper flakes, paprika, and a pinch of salt. Let it sizzle for 30 seconds, then take it off the heat so nothing burns.

Step 4: Bring It All Together
Add your drained pasta to the skillet with the caramelized onions. Pour in some of the reserved pasta water and toss it all together until the noodles are glossy and coated. Drizzle with your homemade chili oil and give it another toss. Taste for salt. Want more heat? Add more chili oil.

Step 5: Serve It Up
Plate that beauty, sprinkle with grated Parmesan or Pecorino if you like, and maybe top with some chopped fresh herbs (parsley, basil, or chives are all great). Serve hot—and definitely don’t skip a final drizzle of chili oil over the top.