For the Breadcrumbs: In a medium skillet, melt butter over medium-low heat. Add grated garlic and cook until fragrant, about 1 minute. Add breadcrumbs and toss to coat. Cook, stirring often, especially towards the end, until breadcrumbs are golden brown, 3 to 5 minutes. Off heat, stir in za'atar, lemon zest, and salt. Transfer to a small bowl and let cool completely before serving or storing in an airtight container until ready to use.
For the Dressing: In a blender, process labneh, feta, lemon juice, vinegar, Worcestershire, mustard, anchovies, garlic, salt, and pepper on until puréed, about 30 seconds. With blender running, slowly add oil and blend until emulsified.
To Assemble Salad: In a large bowl, toss lettuce with prepared dressing. Once lettuce is coated, add half of grated cheese and half of reserved breadcrumbs and toss again to incorporate. Transfer to a salad bowl and sprinkle with remaining cheese and breadcrumbs. Serve.
