01 -
Drizzle olive oil into the bottom of the slow cooker and evenly distribute the sliced red onion on top.
02 -
Arrange beef chuck pieces over the onions. Scatter minced garlic over the beef and season with lemon juice, dried oregano, salt, and black pepper.
03 -
Cover with the lid and cook on low heat for 8 hours, until the beef is fork-tender.
04 -
Remove the lid and use two forks to shred the beef directly in the cooker.
05 -
If desired, warm pita breads by brushing lightly with olive oil and charring both sides in a skillet over medium-high heat for 10–15 seconds per side.
06 -
Using a slotted spoon, serve shredded beef onto warm pitas. Top with diced onion, tomatoes, cucumber, shredded lettuce, and tzatziki sauce as desired.