Dice onions, carrots, and celery into ¼-inch pieces, mince garlic, and rinse lentils under cold water.

Add rinsed lentils, a 28-ounce can of diced tomatoes with juices, chopped carrots, celery, onions, and minced garlic to your slow cooker bowl.

Sprinkle ground cumin, sweet paprika, and dried thyme over the top, nestle in a bay leaf, then season with salt and black pepper.

Pour in vegetable broth until lentils and veggies are just covered.

Set slow cooker to LOW heat and let it cook for 6 to 8 hours.

About 10 minutes before serving, stir in fresh spinach or chopped kale.

Remove bay leaf, taste, then adjust seasonings before serving.