Prepare to be amazed by the power of the humble red onion! This recipe is a love letter to slow cooking, transforming simple onions into a jammy, sweet, and incredibly deep base for a pasta sauce that rivals any restaurant dish. As the onions caramelize and the sauce simmers with rich red wine, tomatoes, and fragrant herbs, your kitchen will fill with the most intoxicating aroma. It’s the ultimate comfort food, perfect for a cozy weekend dinner or for wowing your guests with its complex, sophisticated flavor. Trust me, the patience required is rewarded tenfold with every single bite.
Ingredients
• 2 lbs / 900g red onions
• ½ cup / 113g butter
• 2 to 3 tbsp / 30 to 45 ml olive oil
• ¾ tsp / 4g salt, plus more for pasta water
• 1 to 2 cloves garlic, minced
• 1 quart / 950ml peeled tomatoes, with their liquid
• 2 cups / 475 ml dry red wine
• ½ tsp / 1g dried basil, crushed
• ½ tsp / 1g dried rosemary, crushed
• 1 large bay leaf
• 1 pinch dried marjoram
• Freshly ground black pepper, to taste
• 1 tsp / 4g sugar
• 1 pinch ground cinnamon
• 2 tsp / 10 ml red wine vinegar
• ¼ cup / 40g dried currants
• 1½ to 2 lbs / 680g to 900g penne pasta
Instructions
1. Prepare the onions by peeling, halving, and slicing them thinly. In a large, heavy-bottomed pot or Dutch oven, melt the butter with the olive oil over medium-low heat. Add the sliced onions and cook, stirring frequently, for 30 to 45 minutes. Be patient—you want them to become a deep, jammy, and evenly light brown color. Once caramelized, stir in the salt and minced garlic and cook for one more minute until fragrant.
2. Add the tomatoes, wine, herbs, pepper, sugar, cinnamon, vinegar, and currants. Stir everything to combine, bring to a gentle bubble, then reduce the heat to low. Simmer the sauce, partially covered, for 1.5 to 2 hours, stirring occasionally, until it has thickened considerably and the flavors have melded beautifully. Remove the bay leaf before serving.
3. About 20 minutes before the sauce is done, bring a large pot of generously salted water to a rolling boil. Cook the penne according to package directions until al dente. Reserve about 1 cup of the starchy pasta water, then drain the pasta immediately.
4. Toss the hot pasta and the sauce together in a large, heated serving dish. If needed, add a splash of the reserved pasta water to help the sauce cling to the noodles. Serve immediately.
Nutritional Information
• Servings: 8
• Calories: Approximately 620 kcal per serving
• Protein: Approximately 15g
• Carbohydrates: Approximately 95g
• Fat: Approximately 20g
• Note: This is an estimate and can vary based on exact used.
Pro Tips
• Don’t rush the onions. The slow, patient caramelization over medium-low heat is the secret to developing the deep, sweet flavor base for the entire sauce.
• Always save a cup of the starchy pasta water before draining. It’s liquid gold for emulsifying the sauce and helping it cling perfectly to every piece of pasta.
• Use a dry, full-bodied red wine that you would enjoy drinking, like a Cabernet Sauvignon or Merlot. It adds a significant layer of complexity to the sauce.
• This sauce is even better the next day! Make it ahead of time and let the flavors meld overnight in the refrigerator for an even richer taste.
• Garnish with a sprinkle of fresh parsley, torn basil leaves, and a generous grating of Pecorino Romano or a high-quality vegetarian Parmesan-style cheese.
FAQ
Q: Can I make this red onion pasta sauce vegan
A: Absolutely! To make this recipe fully vegan, simply substitute the butter with a high-quality plant-based butter or use an equivalent amount of extra olive oil. For serving, omit the dairy cheese and use a sprinkle of nutritional yeast or a good vegan Parmesan-style alternative.
Q: How can I add more protein to this vegetarian dish
A: This dish is wonderful as is, but you can easily boost the protein. Try adding a can of rinsed cannellini beans or chickpeas to the sauce during the last 30 minutes of simmering. Serving it with a high-protein pasta, like one made from chickpeas or lentils, is another excellent option.
Q: Is this red onion sauce good for meal prep
A: Yes, this sauce is fantastic for meal prep! The flavors deepen and become even richer overnight. You can store the sauce in an airtight container in the refrigerator for up to 5 days. It also freezes beautifully for up to 3 months, making it perfect for a quick and delicious vegetarian dinner.
Q: What is a non-alcoholic substitute for the red wine
A: For a non-alcoholic version, you can replace the 2 cups of red wine with an equal amount of a rich vegetable broth. To replicate some of the wine’s acidity and depth, add an extra tablespoon of red wine vinegar or a splash of balsamic vinegar to the broth.
