Set pizza crusts on pizza pan then thinly spread pesto all over. Sprinkle mozzarella, then sparingly add dollops of ricotta cheese, followed by parmesan cheese. Evenly distribute chopped up broccoli florets, lemon zest, and a pinch of red pepper flakes.
Transfer to oven and bake for 15 minutes until cheese has melted and broccoli has cooked through. Remove the pizza from the oven and top with fennel fronds. Let cool and enjoy!