Rinse your lentils and look them over carefully for pebbles or debris.
Since cooking the lentils is what takes the longest, start by covering them with cold water or stock and bringing to a simmer.
Add the celery, aromatics, and ham bone and simmer as you prepare the sofrito (the lentils should take about 40 minutes to cook, though this depends on the variety - taste them often so that they don't overcook and become mushy).
Cut 3/4 of the chorizo into rounds, place them in a heavy frying pan and turn up the heat. Sear the chorizo on each side, allowing the fat to render.
Remove the chorizo from the pan and reserve for later. Mince the uncooked 1/4 of the chorizo for later use as well.
In the pan with the chorizo grease, add 1/4 cup of olive oil over a medium heat
Add the onions and cook slowly until starting to brown (about 7 minutes)
Add the carrots and cook another 5 minutes or so, until everything is cooked through and golden
Add the garlic for another couple of minutes
Add the tomatoes, minced chorizo, tomato paste and roasted pepper paste
Cook over medium heat, stirring, until completely reduced to a paste (sofrito)
Add this sofrito mixture to the lentils, and simmer together until all of the flavors are well combined. Taste the lentils often to make sure you don't overcook them.
Once cooked through, remove the aromatics and the celery from the pot and let the soup sit, uncovered, for as long as you can wait (the longer, the better combined the flavors will be)
Serve hot and top with the seared chorizo and some pickled peppers if you can get them!
Enjoy your homemade lentejas con chorizo!
Tip: if you like a thicker version, remove a couple of ladles of lentils before adding the sofrito (make sure they're cooked through) and run this through the blender until smooth. Add back to the soup for a thicker version.