Caramelize the onions in olive oil over medium-low heat, stirring occasionally, until very soft and browned, about 30-40 minutes.
Add the garlic and cook for 2-3 minutes until fragrant.
Pour in the vegetable broth and add the thyme. Season with salt and pepper.
Bring to a simmer and cook for 10-15 minutes until the flavors have melded.
Toss the caramelized onion mixture with cooked pasta.
