Prepare the pizza crust according to the directions on the package or the recipe.
Put the parsley, basil, nuts, 1/4 cup oil, garlic (if using), and salt in your food processor or
blender and blend until relatively smooth, about 2 minutes. With the motor running and the lid
on, add 2 tablespoons water and the lemon juice (if using) through the chute or feed tube.
Blend in another 1 tablespoon water if needed to reach a creamy, thick but spreadable
consistency.
When the crust is ready to be topped, spread with your desired amount of the pesto sauce.
Top with the mushrooms and any of the additional topping options.
Bake for 5 to 10 minutes, or until the toppings are cooked to your liking.
Serve the pizza with crushed red pepper for sprinkling and extra-virgin olive oil for drizzling.
Store leftovers in an airtight container in the refrigerator for up to 2 days.