Onion and Miso Pasta

Name: Onion and Miso Pasta
Prep time: 15 min
Total time: 15 min
Cuisine: Japanese, Mediterranean, European, Asian, Italian
Ingredients: 2 tbsp. Extra-Virgin Olive Oil; 3 tbsp. Unsalted Butter, divided; 2 Large Onions, thinly sliced; Kosher Salt; 4 Garlic Cloves, thinly sliced; 1 tbsp. White Miso Paste; 1 cup Low-Sodium beef, Chicken or Vegetable Broth; Freshly ground pepper; 12 oz. Spaghetti; 1 cup Finely Grated Parmesan, plus more for serving; 1/4 cup 1-inch long cut chives, or the green parts of scallions, thinly sliced on a sharp bias