Instructions

Step 1: Caramelize the Onions

Prepare the Slow Cooker:
Place the sliced onions into the slow cooker. Add the butter, olive oil, salt, and sugar, ensuring that all the onions are well-coated.

Slow Cook the Onions:
Set your slow cooker to low and cook the onions for 8-10 hours. It’s a long time, but this slow process is what gives them their deep, sweet flavor. Stir occasionally if you can, but if you’re out, don’t worry—the slow cooker has your back.

Step 2: Cook the Pasta

Boil the Pasta:
About 15 minutes before the onions are done, bring a large pot of salted water to a boil. Cook your pasta according to the package instructions until al dente. Reserve a cup of pasta water before draining.

Step 3: Combine and Serve

Mix Pasta and Onions:
Once the pasta is drained, return it to the pot. Pour the caramelized onions (along with all the buttery goodness) on top of the pasta. Mix well, adding some of the reserved pasta water as needed to achieve the desired sauce consistency.

Add Cheese and Season:
Stir in the grated Parmesan cheese and freshly ground black pepper. Taste and adjust the seasoning as needed. Serve warm, garnished with parsley if desired.