Purple Sweet Potato Soup

Name: Purple Sweet Potato Soup
Ingredients: 8 slices bacon; 2 pounds purple yams, cut into 1-inch cubes; 3 cloves garlic, minced; 2 sprigs thyme, leaves removed; 1 red onion, sliced; 1 tablespoon fresh oregano; 1 teaspoon ground cumin; 1/2 teaspoon ground coriander; Kosher salt and freshly ground black pepper; 5 to 6 cups vegetable broth; 1 cup chopped roasted and salted pistachios; 1/4 cup chopped fresh parsley, plus more leaves, for serving; 2 tablespoons chopped fresh oregano; 1/4 teaspoon turmeric; Sour cream, for serving