Savory Mashed Sweet Potatoes

Bahan-bahan (6 porsi)

• 4 pounds sweet potatoes (about 7 small-to-medium), peeled and cut into 1″ cubes
• 2 teaspoons salt, divided
• ⅓ cup finely sliced green onion, mostly green parts (from 1 bunch)
• ⅓ cup finely chopped fresh flat-leaf parsley
• 1 small -to-medium garlic clove, pressed or minced
• ¼ cup sour cream*
• 3 tablespoons butter, cubed
• Freshly ground black pepper
• 1 teaspoon extra-virgin olive oil