Slow Cooker Lentil Cauliflower Stew

• 16 ounces dried lentils
• 1 tablespoon olive oil
• 1 large onion, chopped (about 2 cups of onion)
• 2 garlic cloves, chopped
• 1 pound cauliflower, chopped into very small florets
• 2 leeks, white and green parts only, halved, washed carefully, and chopped)
• 2 large carrots, peeled and chopped
• 2 celery stalks, chopped
• 2 bay leaves
• 1 tablespoon chopped fresh thyme or 1 tsp dried thyme
• 2 teaspoons kosher salt (or to taste)
• 1 teaspoon cumin
• 1/2 teaspoon cayenne (very spicy-- add 1/4 tsp or less for a milder flavor)
• 1/4 teaspoon black pepper
• 8 cups low sodium vegetable broth
• 32 ounces diced tomatoes with juice (1 large can)
• 2 cups chopped kale or Swiss chard

Optional Toppings

• Plain yogurt, herbed goat cheese, feta, crème fraîche, grated Parmesan, Greek yogurt or lowfat sour cream