Preheat oven to 170 F. Spread the olives onto two baking sheets.
Bake with the door open a crack for 18-24 hours, or when the olives feel dry and no longer oily.
About 4 hours before you’re finished (the olives should still have a bit of moisture to them), add in the torn pieces of bread. Continue dehydrating until everything is very dry. Remove from the oven, transfer to a food processor and process until it forms small crumbs. Transfer to a container and refrigerate until ready to use. This can be made up to 2 days in advance.
Put the celery root in a medium pot and cover with salted cold water. Bring to a boil and cook until very tender, about 15-20 minutes. Transfer to a food processor and allow the mixture to cool.
Once cooled to room temperature, add in the crème fraiche, mayo, rosemary, zest, juice, and celery seed. Puree until very smooth then season with salt and pepper to taste.
Get a wooden box (I bought a cheap wooden cutlery divider and used that) and fill it with the celeriac dip. Top it with the soil until everything is covered. Then arrange the vegetables in rows, and stick the sprouts into the corners of the box like grass.
Serve with additional vegetables for dipping and enjoy.