French Spring Soup

Ingredients

• ¼ cup butter
• 1 pound leeks, chopped
• 1 onion, chopped
• 2 quarts water
• 3 large potatoes, chopped
• 2 large carrots, chopped
• 1 bunch fresh asparagus, trimmed and cut into 1 inch pieces
• ⅓ cup uncooked long-grain white rice
• 4 teaspoons salt
• ½ pound fresh spinach
• 1 cup heavy cream