Shredded Beef Tostadas

Step 1
Prepare spice rub: Combine chili powder, paprika, oregano, garlic powder, onion powder, coriander, cumin, salt, and pepper in a bowl.

Step 2
Rub 1 tablespoon of the spice rub on each side of the chuck roast. Set remaining spice rub aside for later.

Step 3
Heat oil in a skillet over medium heat. Place seasoned roast in the hot oil and brown for 2 to 3 minutes per side. Remove to a plate and keep warm.

Step 4
Cook onions in the same skillet, stirring frequently, until they begin to turn clear, 2 to 3 minutes. Add garlic and cook until fragrant, about 1 minute. Stir in beef stock, 1/2 cup chopped tomato, orange juice, lime juice, and remaining spice rub.

Step 5
Return the roast back to the skillet and bring to a boil. Cover, reduce heat, and simmer gently until meat is tender and cooked through, about 2 hours. Remove meat from the skillet and transfer to a cutting board.

Step 6
Carefully pour the skillet contents into a blender or food processor. Pulse several times, until sauce is smooth.

Step 7
Remove the visible fat from the meat and discard. Shred the meat with two forks. Place shredded beef back into the skillet with about 3/4 cup of the pureed tomato sauce. Add more, if desired, to adjust the consistency. Refrigerate any unused tomato sauce in a sealed container for another use, if desired.

Step 8
To assemble tostadas, spread about 1/3 cup refried beans on each tostada shell. Top with layers of shredded beef mixture, lettuce, Cheddar cheese, and reserved chopped tomatoes. Drizzle with salsa and add a dollop of sour cream and guacamole. Garnish with cilantro and serve with lime wedges.