
Thinly slice the onions. Heat the butter and oil in a large skillet over low to medium-low heat, then add the onions and salt. Cook slowly, stirring every few minutes, until the onions are very soft, golden brown, and jammy, about 45 to 75 minutes. Stir in the minced garlic during the final minute and cook just until fragrant.


While the onions cook, bring a large pot of well-salted water to a boil. Cook the farfalle according to the package directions until al dente. Reserve a little pasta water, then drain the pasta and let it cool slightly so it will not thin or break the creamy dressing.



In a large mixing bowl, whisk together the sour cream, mayonnaise, red wine vinegar, soy sauce, Worcestershire sauce, and black pepper. If the dressing feels too thick, loosen it with 1 to 3 tablespoons of cooled reserved pasta water.

Add the cooled pasta and caramelized onions to the dressing and toss until evenly coated. Taste and adjust with more salt, pepper, or vinegar if needed. Garnish with sliced green onions and serve warm, at room temperature, or chilled.






