Top with more of the onion mixture, leaving some in the saucepan.
Spread the onion mixture over the dough right to the edge.
Place the skillet with the remaining onion mixture over medium heat.
Cover dough with onion mixture to within 1/2 inch of edge.
Stir peas into onion mixture and cook 2 or 3 minutes.
Add the onion mixture to the bowl with the root vegetables.
When the potatoes are cooked, add them to the onion mixture.
Top the potatoes with the goat cheese and then the onion mixture.
Chop the tomatoes and add them to the onion mixture.
In the same skillet, add the onion mixture and the vinegar.