Mix the vegetable broth with all of your spices, and then place the mixture in your slow cooker.
Add the cubed sweet potatoes/yams and onion and cook on high for 3-3.5 hours. The vegetables should be soft for the next step.
Mix in the (rinsed) red lentils and then cook (still at high) for another 1.5 hours - 2 hours.
Before serving, add the thickened plant-based milk* (see notes) and mix thoroughly. Then slowly mix in some water until you reach the desired consistency.
Serve hot, seasoned with sea salt to taste.
Thickened non-dairy milk: Combine your favorite low-fat plant-based milk (such as soy, almond, cashew, or hemp milk) with 2-3 Tbsp of corn starch, arrowroot powder, or potato starch and whisk well. Or, combine 1/4 cup of cashews with about 12oz of water and blend in a high-speed blender until creamy and smooth.