Chop half of the broccoli crown into a medium dice (much smaller than bite size; each floret should be about the size of a dime). Set aside to use as pizza toppings.
In a food processor chop the other half of the broccoli crown with the garlic until very fine.
In a medium saucepan, melt the butter over medium-low heat. Add the flour and whisk to form a paste. Slowly stream in about half of the cream, whisking constantly, until a thick but smooth sauce forms.
Remove the pan from the heat and stir in the broccoli-garlic mixture and remaining cream. The mixture will probably be quite thick at this point. If it is not spreadable, return the pan to low heat and whisk in milk, a few tablespoons at a time, until the sauce thins enough to spread with a spoon. Remove from heat and set aside.
Place a baking stone or large cookie sheet into the oven. Heat the oven to 500°.
Divide the pizza dough in half. Roll or press the first half out to a 14" circle. Place the dough on a cornmeal-covered pizza peel or a sheet of parchment, to facilitate sliding the pizza into the oven.
Spread the crust with half of the sauce, followed by half of the cheese and half of the diced broccoli.
Slide the pizza onto the heated stone and bake for 10 minutes.
Repeat with the remaining crust, sauce, cheese, and broccoli.
Top the pizzas with crushed red pepper, to taste.