I have a question about the ingredient "Brown or French lentils, rinsed and picked over" on the recipe "Lentil sausage kale soup" from Andra. Can I substitute red lentils in this recipe?
This is not my recipe but I don't see why not. You can kick up a rucus on which lentils are "best" for anything (in Italy they will go with Casteluccio from Umbria) but largely they are interchangeable.
Although lentils are generally interchangeable, I find the red ones cook much faster than either the brown or green lentils. So perhaps adapt the cooking time for the dish, or add the lentils later.
Personally, I wouldn't sub red lentils here.
It would still taste great, but the texture and appearance of the soup would change. Red lentils cook down to a puree in the cooking time for this recipe. A possible way to use them where they stay intact is to leave them out while you cook the rest of the soup; pour boiling water over the red lentils so that they absorb the water but do not lose their shape; then add them to the soup for a final short simmer so they can pick up flavor. (Compare to making split pea soup.)
This is a technique I use for making tabbouli with bulgur and red lentils. You can see how I do it here -- http://www.food52.com/recipes...
I have never used red lentils but from what I understand, as the others have said, they cook faster and are better for a puree. I am guessing that the red lentils would give your soup a very thick consistency. I normally use regular brown lentils that you find in the grocery store. I have also used beluga lentils which held their shape. Both were good.