Bake your cauliflower crust according to your package directions except place it directly onto your oven rack instead of a cooking sheet! Remove from oven once baked and turn heat to 400 degrees.
On a sheet pan lined with foil, place butternut squash cubes on one side and shaved Brussels sprouts on the other. Drizzle with olive oil and season everything with salt, pepper and garlic salt. Roast for 20 mins then remove to cool.
In a food processor, combine roasted squash, 1/4 cup almond milk and 1 tbs. parmesan until smooth like pizza sauce. Top crust with an even layer (more sauce for thinner crust, less sauce for doughier), then top with 3/4 cup mozzarella cheese. layer on roasted shaved brussels sprouts then top with remaining mozzarella and 1 tbs. grated parmesan.
Bake for 10 minutes or until cheese is melted and bubbling. Remove from oven and top with shaved prosciutto! Serve warm or at room temp.