Mustard Green, Spinach and Potato Soup

Topped with chopped spinach and Havarti cheese, this soup is great served with sweet potato or pumpkin cornbread.

4 Tablespoons olive oil
2 cups onions, chopped
2 lbs yukon gold or russet potatoes, peeled cut into 1 inch pieces
8 cups chicken stock
2 teaspoons crushed red pepper (optional)
4 garlic cloves, minced
3-4 cups mustard greens, stems removed and coarsely chopped
2-3 cups spinach, coarsely chopped 
1 cup sour cream

1. Heat 2 tablespoons oil in heavy large pot over medium heat. Add onions and sauté until tender and golden, about 8 minutes. Add potatoes; sauté 3 minutes. Add 8 cups chicken stock and crushed red pepper. Bring to boil. Reduce heat. Simmer until potatoes are tender, about 20 minutes.
2. Meanwhile, heat remaining 2 tablespoons oil in another heavy large pot over medium heat. Add garlic; sauté until fragrant, about 1 minute. Add mustard greens and all but 1 cup spinach leaves; sauté until wilted, about 3 minutes.
3. Add sautéed greens to potato mixture. Working in batches, purée soup in blender until smooth.  Return soup to pot.  Season soup to taste with salt and pepper.
4. Coarsely chop the remaining 1 cup spinach leaves. Ladle soup into bowls. Add dollop of sour cream to each bowl. Garnish soup with sliced spinach leaves and serve.

*Adapted from