Ubi Jalar, Kangkung, dan Sosis Panggang dengan Saus Keju Putih

Bahan-bahan (4 porsi)

• 2 teaspoons olive oil
• 2 medium sweet potatoes, peeled and cubed (3-4 cups)
• 16 ounces Italian pork or chicken sausage, cut into small rounds
• 2 cups low sodium chicken broth
• 3/4 cup milk
• 1/4 cup flour
• 3/4 cup shredded Gruyere cheese
• 2 cups finely chopped kale