Bring a small pot of water to a boil (about 4 cups of water). Using a sharp, serrated knife, slice a small "X" at the bottom of each tomato, and place them in a medium bowl. Pour the hot water over them, and allow to soak for a minute. Remove and peel by grabbing the skin on of the corners created by the "X".
Slice in quarters and place in a bowl of a food processor fitted with a blade, along with the white onion, cucumber, and red pepper. If the cucumber has a lot of seeds, scoop them out with a spoon, and chop up the remaining flesh. If the cucumber has a thick waxy skin, remove it as well.
Remove the husks from the tomatillos, rinse well, and halve. Slice the Serrano pepper in half lengthwise, seed, and mince. Add the tomatillos and Serrano to the bowl of the processor, along with the minced garlic.
Process to a smooth texture, or the texture you prefer, and pour into a stainless steel bowl. If the bowl of your processor it too small to accommodate all of these ingredients, first process the tomatoes, onion, and cucumber together, and pour into the bowl. Replace the bowl of the processor and re-fit the blade, and add the red pepper, tomatillos, Serrano and garlic. Process, and pour to the same bowl.
Using a balloon shaped whisk, whisk the sherry wine vinegar, olive oil, red wine, Worcestershire sauce, and salt.
Remove approximately three cups of the soup and pour back into the food processor. Add the soft bread in pieces, and process until smooth. Pour back into the bowl, and stir into the remaining soup.
Cover with plastic and chill for 4 hours or ideally overnight before serving.
The 4-hour cook time is actually the time required for chilling the soup in the refrigerator.