Dice the boneless chuck roast into bite-sized cubes, trimming off any large pieces of fat.
In a large, heavy skillet or Dutch oven, heat 2 tablespoons of Mazola® Corn Oil over medium-high heat. Add the beef cubes in batches (avoid overcrowding the pan) and sear until browned on all sides. Remove the beef from the pan and set aside.
While the beef is browning, prepare the sauce. In a blender, combine: tomatoes, garlic cloves, onion, guajillo chiles, oregano, cumin, tomato bouillon, salt, and water. Blend until smooth.
Return the browned beef to the skillet. Pour the blended sauce over the meat, making sure all pieces are coated. Stir well.
Reduce the heat to low, cover the pot, and let the beef simmer gently for 45 minutes to 1 hour, or until the meat is tender and the sauce has thickened. Stir occasionally and add a splash of water if the sauce becomes too thick.
Stir in the diced potatoes. Cover again and cook for an additional 15–20 minutes, or until the potatoes are fork-tender and the flavors have melded together.
Serve the carne guisada hot, with Mexican rice and a tortilla. Enjoy!