Important Note about Salt: Not all salts are made equal and cannot be substituted 1:1. If you are substituting table salt for kosher salt, you will need to cut the amount called for in the recipe by at least half.
Simmer on low heat. You don’t want the lentils to cook too quickly, so make sure the heat is on low when simmering.
If using a blender instead of an immersion blender, vent for steam. Otherwise, too much steam pressure can build in the blender and you'll end up with a mess or you may get burned. Use a kitchen towel to hold down the vented lid in your blender.