Preheat the oven to 400 degrees F. Line a baking sheet with foil or parchment. Toss the sliced veggies in one tablespoon of the olive oil. Season with the oregano, salt, and pepper. Spread them out in a single layer on the baking sheet. Bake for 18 to 20 minutes until tender.
Let the pizza dough sit at room temp while the veggies roast. When the veggies are finished, adjust the oven temperature to 450 degrees F. Transfer the dough to a lightly floured surface and roll it out into an oval. Place the dough on a baking sheet. The oval should take up most of the room on a standard baking sheet. You can also roll the dough into a thinner crust, but you will need to decrease the cooking time by a couple of minutes to avoid burning. In a small bowl, mix together two tablespoons of olive oil with the minced garlic and rosemary. Brush this mixture on top of the dough. Season with salt and pepper, and sprinkle with half of the parmesan cheese. Bake for 3 to 4 minutes.
Remove the dough from the oven and place the roasted veggies on top. Sprinkle with the rest of the cheese. Return the pizza to the oven and cook for 6 to 8 minutes until the cheese is melted and the crust is golden brown.
Slice the flatbread into pieces before serving. Serve warm or store the pieces on covered platter in the fridge for up to a few hours before serving.
Possible additions or substitutions include corn, green beans, or eggplant. The flatbread would also taste delicious with fresh basil and a drizzle of balsamic reduction.