I have an awesome lentil soup recipe. went to grab the lentils, alas they are yellow split peas! do I just use them, or get my lentils? Y or

Look op a recipe for toor dhal soup which uses these or just make your recipe. May need to add more liquid and cook longer.

The yellow split peas will take much longer to cook than lentils. Some recipes soak them first.

I would say that it depends on how critical texture is to the success of the soup. While lentils and split peas have somewhat different flavors, the difference isn't dramatic enough to be critical in my opinion. Texture, though could be the big issue.