Step 1

Warm water and vegetable bouillon in a slow cooker on High until dissolved. Add lentils, carrots, and potatoes.

Step 2

Heat a medium saucepan over medium heat. Add cumin and coriander and cook and stir until fragrant, about 20 seconds. Add oil, followed by onion. Cook, stirring occasionally, 2 to 3 minutes. Add garlic and saute for 30 seconds. Remove from heat and transfer to the slow cooker. Stir. Add tomato paste, salt, and pepper. Stir in spinach.

Step 3

Cook on High, stirring every 30 minutes, until lentils are tender and stew has thickened, 3 to 4 hours.