In the same pot, bring the milk and water to a simmer. Add the cauliflower and cook until just tender - about 3 minutes, drain. Add the cauliflower to the barley along with the shallots, celery, herbs, preserved lemon, lemon juice, white wine vinegar,extra virgin olive oil, salt and white pepper. Toss to combine. Taste and adjust seasoning. Sprinkle with breadcrumbs and serve with the lebne or burrata.