In a large bowl toss the veggies and rosemary with the oil and some salt and pepper. Spread out into an even layer on a baking sheet and bake at 400°F for 30 minutes or until tender and lightly browned. Remove from oven, toss in pancetta then set aside to cool.
For the crust, prepare the pastry as directed then roll out between 2 layers of parchment (dust with a bit of GF flour) to about 16" round and 1/8" thick, then place on a baking sheet and remove top layer of parchment.
Spread goat cheese on pastry, leaving a 2 inch border. Spread the veggie mixture over top of cheese, piling it a bit higher in the center, then fold over the edges of the pastry over filling. For a browner crust, brush the pastry edges with a beaten egg.
Bake at 400°F for 40-45 minutes until crust is golden brown. Serve warm or at room temperature.