These were labor intensive little nests, but worth it.  I used silicone cupcake pans.  The dark root veggies, mostly purple potatoes, plus a little parmesan to hold them together and a few herbs were julienned, then pressed in the pan with oiled aluminum foil holding their hollow shape.  I have no idea how long I baked them, but I think the temp was about 400f.  When cold (actually defrosted) I pressed some avocado at the bottom and put in marinated quail egg, mozarella round cheese, cipioni onion, and kalamata olive, surrounded it all with a fiddle leaf fern, 1/4 tiny artichoke, Nice olives, cherry tomato, all on a bed of watercress and a couple more herbs.  It was meant to appeal to children as well and it did.