Rinse 1 cup of brown or green lentils under cold water until water runs clear. Set aside.

In a skillet over medium heat, add olive oil and sauté 1 chopped onion and 2 minced garlic cloves for 3-4 minutes until translucent. Transfer to the slow cooker.

Add the rinsed lentils, 2 cans of diced tomatoes, and 4 cups of vegetable broth to the slow cooker with the onion and garlic. Add 1 teaspoon of ground cumin, 1 teaspoon of smoked paprika, 1 teaspoon of dried thyme, and a bay leaf. Season with salt and black pepper to taste.

Cover and cook on low for 6-8 hours or on high for 3-4 hours until lentils are tender.

Remove the bay leaf and stir in 2 cups of chopped spinach or kale, letting them wilt for about 5 minutes.

Taste and adjust seasonings if needed. Add more salt, pepper, or red pepper flakes for heat.

Serve in bowls garnished with freshly chopped parsley and a squeeze of lemon juice.