Bring a large stock pot with water to a boil. Add florets and cook until tender and falling apart, about 30 minutes. Drain and let cool. Working in batches, place cauliflower on a large clean dish towel. Squeeze out the excess moisture of the cauliflower. Don’t skip this step, it helps keep the crust firm.
Line a baking sheet with parchment. Spray with cooking spray.
In a large bowl, add the cauliflower, egg and Parmesan; mix well. Press the dough into a 1/2-inch-thick circle on the prepared baking sheet. Bake until the crust is golden brown and the edges are crispy, 20 to 25 minutes.
In a small bowl, add basil, parsley, garlic, Parmesan, chili flakes and olive oil. Whisk to form a paste.
Remove pizza crust from oven. Spread with herb pesto. Top with tomatoes and cheese. Return to oven for another 10 minutes. Remove from oven. Let sit for 5 minutes. Cut into slices and enjoy.