01 -
Bring a large pot of generously salted water to a rolling boil. Cook your pasta according to package directions until it's al dente - tender but still firm to the bite. Drain, reserving a small cup of the starchy pasta water just in case you need it later.
02 -
While the pasta water is heating, warm olive oil and butter in a large, deep skillet over medium heat. Add your thinly sliced onions along with the sugar and salt. Cook them slowly, stirring occasionally, for about 25-30 minutes. Take your time here - good caramelization can't be rushed! The onions should gradually transform from sharp and pungent to sweet and golden brown.
03 -
Once your onions have reached that beautiful caramel color, add the minced garlic to the pan. Cook for just 1-2 minutes until you can smell that gorgeous garlic aroma. Be careful not to let it burn as garlic can become bitter quickly.
04 -
If you're using white wine, pour it into the hot pan and enjoy the satisfying sizzle as it deglazes the surface. Use a wooden spoon to scrape up all those flavorful browned bits from the bottom of the pan. Let the wine simmer until it's mostly evaporated, concentrating its flavor.
05 -
Pour in the broth and heavy cream, giving everything a good stir to combine. Let this mixture simmer gently for about 5 minutes until it begins to thicken slightly. You'll notice the sauce taking on a beautiful light golden color from the caramelized onions.
06 -
Add the grated Parmesan cheese, stirring until it melts completely into the sauce, creating a smooth, creamy texture. Taste and adjust the seasoning with salt and freshly ground black pepper as needed.
07 -
Add your drained pasta directly to the sauce in the skillet. Toss everything together until every strand is coated with the luxurious sauce. If the mixture seems too thick, add a splash of the reserved pasta water to loosen it up. Divide between warmed plates and finish with a sprinkle of fresh parsley and extra Parmesan if desired.