Wash the lentils with plenty of water and place in a medium pot with 4 cups of vegetable stock or water, add the red pepper and paprika; cook for 25 minutes over medium-low heat. The lentils should be soft but not mushy since they must still cook with the guiso.
While the lentils cook, make the guiso or defrost if frozen.
Add the guiso to the lentils, and cook over medium-low heat until the lentils have s°Ftened completely without loosing their shape,
about 45 minutes to one hour.