Preheat your oven to 400°F (200°C). This temperature is ideal for roasting the cauliflower and ensuring the puff pastry becomes golden and flaky.
Wash and cut the cauliflower into florets. Toss them with a drizzle of olive oil, salt, and pepper. Spread the florets on a baking sheet lined with parchment paper. Roast in the preheated oven for about 20-25 minutes, or until they are tender and slightly browned.
While the cauliflower is roasting, take your puff pastry shell out of the freezer and allow it to thaw according to the package directions. This usually takes about 30 minutes.
Once the cauliflower is done roasting, remove it from the oven and allow it to cool slightly. On the thawed puff pastry shell, spread the BBQ sauce evenly across the surface.
Layer the roasted cauliflower slices on top of the BBQ sauce. Sprinkle the shredded mozzarella cheese over the cauliflower, followed by the corn, petite black beans, chopped red pepper, and chopped green pepper.
Place the assembled pizza back in the oven and bake for an additional 15-20 minutes, or until the cheese is melted and bubbly, and the edges of the pastry are golden brown.
Remove the pizza from the oven and let it cool for a few minutes. Slice it up and serve warm, garnished with fresh cilantro or green onions if desired.