Preheat Pannini press to 200° . Rub press with an oiled cloth on both sides.
To assemble sandwich:
Smear the pesto on the inside of the focaccia round on both sides. On one side, put the eggplant slabs. On the other side put the portabella slabs. If necessary cut vegetables to fit focaccia round. Crumble the goat cheese over the mushroom and put the roasted peppers on top.
Put together and brush the outsides with olive oil and cook in the Pannini press for 2 minutes until toasted.
Toss mixed greens in vinaigrette and stuff inside the hot sandwich.
Cut in thirds and pierce each third together with picks in a line. Place in front of plate, place accompaniment behind sandwich on plate.
Place olive garnish to right side of sandwich. Serve.