Slow-Cooker Butternut Squash Soup

Ingredients

• 1 tablespoon olive oil
• 1 large onion, chopped
• 2 garlic cloves, minced
• 1 medium butternut squash (about 4 pounds), peeled and cut into 1-inch pieces
• 1 pound Yukon Gold potatoes (about 2 medium), cut into 3/4-inch pieces
• 2 teaspoons minced fresh thyme or 3/4 teaspoon dried thyme
• 1 teaspoon salt
• 1/4 teaspoon pepper
• 5 to 6 cups chicken or vegetable broth
• Sour cream, optional