1cupparmesan-cheddar cheese(or simply parmesan or white cheddar)
¼teaspoonblack pepper
2teaspoonfresh thyme leaves
Instructions
Heat three tablespoons of butter in a wide pan. Add thinly sliced onion rings and ½ teaspoon salt, then cook over very low heat for 40-60 minutes, stirring occasionally, until deeply golden.
Cook pasta according to package instructions until just shy of al dente. Drain and set aside, reserving 1 cup of pasta water.
Stir minced garlic into caramelized onions and toast for 30 seconds or until fragrant. Deglaze with white wine and apple cider, scraping up any browned bits from the bottom of the pan, and reduce until almost evaporated. Add broth and Dijon mustard, then simmer 5-8 minutes.
Add pasta to the sauce, along with heavy cream, grated cheese, remaining salt, and pepper. Gradually mix in splashes of pasta water until the pasta is glossy and the desired texture is achieved.
Top individual servings with additional cheese and fresh thyme leaves.
Notes
I like to leave the onions in whole rings for a more rustic look, but you can cut them into half-moons or crescents if you prefer.
I only used about ½ cup pasta water, but you may find you need more/less.
Low and slow is the way to go for caramelized onions. Depending on your pan, heat, and onion quality, caramelization time may vary.
Caramelized onions should be deeply golden, soft, and jammy before building the sauce.
Use a wide, heavy-bottomed pan to caramelize the onions. More surface area helps moisture evaporate, while a heavy base distributes heat more evenly.
If the finished pasta tastes overly sweet or rich, stir in apple cider vinegar or white wine to taste, ¼ teaspoon at a time.
Store leftovers in an airtight container in the fridge for up to 3-4 days.