Rinse the lentils, discarding any pebbles or debris. Cover them with the chicken stock and bring to a simmer. Add the ham bone, celery, and aromatics and simmer until tender, about 40 minutes.
Slice three-quarters of the chorizo into rounds, then mince the remaining chorizo for later. Brown the sliced chorizo on both sides in a skillet over medium-high heat.
Add ¼ cup of olive oil to the rendered fat and turn the heat to medium. 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 and cook for another couple of minutes, then add the tomatoes, minced chorizo, tomato paste, and roasted pepper paste. Cook over medium heat, stirring occasionally, until the mixture has reduced to a thick paste (sofrito).
Add the sofrito to the lentils, and simmer until the flavors are well combined. Taste the lentils often to make sure you don't overcook them.
Once the lentils are cooked through, remove the aromatics and the celery and let the soup sit uncovered. The longer you wait, the better the flavors will be! You can even refrigerate it overnight at this stage if you like.
Serve hot and top with the seared chorizo and some pickled peppers if you can get them! Enjoy!