I had an old callos recipe that had undergone a few revisions, but thereโs always room for improvement. This slow cooker callos beats the old recipe by ten notches.
But, first, what is callos?
It is a stew common in Spain. The meat is mainly beef tripe; blood sausage, bell peppers and chickpeas are almost always present. It is one of the many dishes that Spain introduced in its colonies, and the Filipinos adapted it with local twists.
About beef tripe
There are three kinds of tripe. All come from the cowโs stomach but each is from a different chamber.
Thereโs honeycomb tripe (so-called because the surface looks like a honeycomb), blanket tripe (smoother surface) and book or leaf tripe (thin leaves attached together on one side).
Iโve often used honeycomb tripe to cook callos in the past but I have discovered that blanket tripe is a better choice. It has more of that melts-like-butter texture when cooked to ultra tenderness.
Tripe is commonly bleached with a chlorine solution before it is sold (in the Philippines, at least). Itโs a cleaning process more than anything else. But bleaching also gives tripe its whitish appearance. Pre-boiling the tripe with a little vinegar before cooking removes any lingering odor of chlorine.
Why is a slow cooker ideal for cooking callos?

The first reason has to do with motion. On the stovetop, the heat at the bottom of the pot causes the liquid to rise and bubble, and make the pieces of meat dance around.
The constant movement may cause the pieces of meat to break apart when they are already tender. Plus, because stirring is required to make sure that there is no scorching at the bottom of the pot, the additional agitation doubles the chances of breakage.
But because the stew barely simmers in the slow cooker and no stirring is necessary, it is possible to bring the meat to that level of tenderness that is literally melt-in-the-mouth but with very little chance of ruining the perfectly cut pieces.

The second reason is convenience. The callos cooked overnight while we slept. In the morning, I sauteed the vegetables in olive oil, dumped the cooked meat and sauce into the pot with the vegetables, and the callos was ready for the dining table.
The third reason is flavor. Stews are always better the next day after reheating but this slow cooker callos did not need to sit overnight in the fridge to allow the flavors to deepen. That happened inside the slow cooker.
Slow cooker callos

Ingredients
- 500 grams honeycomb or blanket beef tripe
- 700 grams beef kneecap - (or use beef leg which is more traditional)
- 6 cups bone broth
- 1 to 2 chorizo de Bilbao - sliced into rings
- 2 tablespoons minced garlic
- ยฝ cup chopped onion
- 1 bay leaf
- 1 sprig oregano - stripped
- 2 bird’s eye chilies - finely sliced
- โ cup tomato paste
- salt
- pepper
- 2 tablespoons olive oil
- ยฝ cup cubed carrot
- ยฝ cup diced bell peppers
- ยฝ cup canned chickpeas - (garbanzos), well drained
- ยฝ cup sliced olives - (optional but recommended)
Instructions
- Place the tripe and kneecap (bones and all) in a pot. Cover with water. Boil on the stovetop for 10 minutes. Drain. Throw out the water.
- Place the tripe and kneecap in the slow cooker. Pour in enough broth to cover. Cook on HIGH for three hours.
- Scoop out the tripe and kneecap. They will still be tough at this stage so use a sturdy knife. Cut the tripe into strips about an inch wide. Separate the kneecap bones from the meat and tendons. Cut the meat and tendons into strips.
- Take a cup of broth from the slow cooker and stir the tomato paste in it.
- Put the tripe and kneecap (including the bones) back into the slow cooker. Add the chorizo, garlic, onion, bay leaf, oregano, chilies and diluted tomato paste. Season with salt and pepper. Stir. Set the slow cooker to LOW and cook for another 12 hours.
- Heat the olive oil in a pot. Add the carrot cubes, diced bell peppers, chickpeas and olives. Cook over medium heat until the carrot cubes are cooked but still a little crisp. Sprinkle with salt and pepper.
- Fish out the bones from the slow cooker and discard. Pour the contents into the pot with the vegetables. Stir. Cook just until simmering.
- Serve your slow cooker callos with rice or bread.