I made this for my parents and brothers tonight and the praising response was relentless. I toasted the bread and made the celery root/dairy puree beforehand. I doubled the thyme and it was AWESOME! I baked it until the top was brown, crispy and bubbly. Next time I might double the celeriac because the flavor is awesome and mimics dairy so well. I love this dish and will be making it frequently. It is a pleaser for even the pickiest of blue cheese eaters.