1. Rinse the tripe under cold running water, drain. 2. Cut the tripe into thin shreds. Chop the shreds into one inch lengths. Set aside. 3. Chop the bacon and cook in a large dutch oven. Add the onion and cook until onion is translucent. You may need to add a bit more oil. Add the tripe, red bell peppers, leek, celery, carrot, garlic and cook, stirring for about two minutes. Stir in the serrano chile pepper, beef stock, tomato juice, knuckles and all the spices. Bring to boil, reduce heat and simmer slowly for three hours. You must do this for the tripe to become tender, you don't want it chewy. 4. Add the potatoes and spinach, cook until potatoes are tender 20-30 minutes. 5. Melt the butter, add the flour and whisk, slowly add the cream and continue to whisk until smooth to make a roux. Add the roux to the simmering soup and stir for a few minutes.