Very Slow-Roasted Yams With Seven-Herb Sauce Recipe - Los Angeles Times

Ingredients

• 4 1/2 pounds medium yams or sweet potatoes (5 to 6), peeled
• 5 tablespoons everyday olive oil, divided
• 1 1/2 teaspoons Diamond Crystal kosher salt, plus more
• Freshly ground black pepper
• 1 large egg
• 1/4 cup buttermilk
• 1/4 cup full-fat plain Greek yogurt
• 1/4 cup sour cream
• 2 tablespoons fresh lemon juice
• 1 cup firmly packed flat-leaf parsley, watercress and/or baby arugula leaves
• 1 cup firmly packed chives, sorrel, chervil and/or dill