Lentil and Sausage Soup with Kale

INGREDIENTS

• Salt
• 2 sprigs thyme
• 1 tablespoon bacon fat (or add another tablespoon of olive oil)
• 3/4 cups chopped celery
• 1 cup chopped carrots
• 1 medium onion, chopped
• 3 cloves garlic, chopped
• 1 sprig rosemary
• 1 1/2 cup chopped kale
• 4 chicken sausages (or substitute another kind of sausage)
• 28 ounces canned chopped tomatoes (I use tetra-pack)
• 1 1/2 cup french green lentils, rinsed
• 1 tablespoon olive oil, plus more for browning the sausages