Preheat the oven to 400°F. If you're using a baking stone/steel to bake your pizza, place the stone/steel in the bottom third of the oven before you start preheating).
In a large bowl, toss the cauliflower florets with the oil until evenly coated. Spread them out on a baking sheet, sprinkle with salt and pepper, and roast for 20 minutes, stirring halfway through, or until the cauliflower is tender and golden. Remove it from the oven and set aside.
Increase the oven temperature to 500°F (if using a baking sheet to bake your pizza) or the highest temperature your oven will allow (if using a baking stone/steel). If you're using a baking stone or steel, once the oven has reached its highest temperature, switch the oven setting to Broil on high and let it heat up for about 15 minutes.
While the cauliflower roasts, prepare the sauce. Melt the butter in a small saucepan over medium heat, then remove the pan from the heat and whisk in the hot sauce and salt.
Stretch or roll out your dough to a 12- to 14-inch circle, then transfer it to an oiled or parchment-lined baking sheet or a lightly floured pizza peel (if using a baking stone/steel).
Brush the dough lightly with olive oil. Transfer to the oven and parbake for 2 to 5 minutes, just until the crust is light golden and slides easily on the baking sheet or stone/steel.
Carefully remove the parbaked crust from the oven. In a large bowl, toss the roasted cauliflower with the Buffalo sauce until each piece is well coated. Using a slotted spoon, transfer the cauliflower to the par-baked crust; drizzle with some extra sauce if desired (but be careful not to add too much, as that will make the pizza soggy). Scatter the blue cheese on top.
Transfer the pizza to the oven and bake until the crust is golden and the cheese has browned in spots—about 5 minutes on the baking sheet, 3 to 4 minutes on the baking stone/steel.
Let the pizza rest for 5 minutes, then sprinkle the parsley over top; slice and serve.