Preheat oven to 450 degrees.
Bake crust directly on oven rack for 5 minutes. Remove from oven to cool.
Meanwhile, wash and cut broccoli into about 3-inch long spears, using florets and tender stems only. Toss the broccoli with the oil and pinch of salt. Arrange the broccoli in an even layer on a sheet pan and roast at 450 degrees for 10 minutes. Remove from oven to cool.
Add the peeled and seeded avocado, cream cheese, garlic, lemon juice, parsley, buttermilk and salt to the bowl of a food processor and process until completely smooth.
Spread the avocado dressing evenly on top of the pizza crust. Top the dressing with half the Parmesan cheese.
Chop the broccoli and spread evenly atop the pizza. Top with remaining Parmesan cheese.
Chill and cut pizza into squares to serve.