Description

This Slow Cooker Caramelized Onions Pasta recipe offers a rich and comforting dish featuring deeply caramelized onions cooked low and slow for hours, combined with creamy Parmesan and tender pasta. Perfect for an easy, hands-off weeknight dinner or cozy weekend meal, the sweet and savory flavor of the onions perfectly complements the creamy texture and herbs, making it a delicious vegetarian main course.

Ingredients

Scale

Caramelized Onions

4 large yellow onions, thinly sliced
3 tablespoons unsalted butter
2 tablespoons olive oil
1 teaspoon salt
1/2 teaspoon black pepper
1 teaspoon sugar

Additional Flavorings

3 cloves garlic, minced
1/2 cup vegetable broth
1 tablespoon fresh thyme leaves or 1 teaspoon dried thyme

Pasta and Finishing

12 oz pasta such as fettuccine or spaghetti
1/2 cup grated Parmesan cheese
1/4 cup heavy cream

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Instructions

Prepare the Onions: Place the thinly sliced onions, butter, olive oil, salt, pepper, and sugar into the slow cooker. Stir well to coat the onions evenly with the fat and seasonings.
Slow Cook Onions: Cover and cook on low for 8 to 10 hours, stirring occasionally if possible. The onions should become deeply golden and caramelized, developing a sweet, jam-like texture.
Add Garlic: Stir in the minced garlic and continue cooking in the slow cooker for an additional 15 minutes to infuse the flavor.
Incorporate Broth and Thyme: Add the vegetable broth and fresh or dried thyme to the slow cooker. Mix thoroughly to combine all the flavors.
Cook Pasta: Meanwhile, bring a large pot of salted water to a boil. Cook the pasta according to package instructions until al dente, then drain well.
Add Cream and Combine: Stir the heavy cream into the slow-cooked onion mixture and let it warm through in the slow cooker for a couple of minutes.
Toss Pasta and Serve: Mix the cooked pasta with the creamy caramelized onions in the slow cooker or a large bowl. Stir in the grated Parmesan cheese until evenly combined. Serve warm, garnished with extra Parmesan if desired.

Notes

For even deeper flavor, cook the onions longer until they are very dark and jam-like in texture.
Gruyere or Pecorino Romano cheeses make excellent substitutes for Parmesan.
Add sautéed mushrooms or fresh spinach to the pasta for additional texture and nutritional value.