Step 1

Drizzle the olive oil into the bottom of the slow cooker. Place the red onions over the olive oil.

Step 2

Arrange the roast over the onions. Drop the garlic over the roast and season the pieces with the lemon juice, oregano, salt, and black pepper.

Step 3

Place the lid over the slow cooker and cook on low for 8 hours.

Step 4

Remove the lid and shred the beef with two forks.

Step 5

Warm the pita breads if desired (char them slightly). Serve the beef with a slotted spoon over pitas. Top as desired with onion, tomatoes, cucumber, lettuce, and tzatziki sauce.