Spinach Artichoke Pizza

) homemade or store bought pizza dough*

fresh spinach (, divided)

butter

all-purpose flour

milk

onion powder

Salt and freshly ground black pepper

garlic (, minced)

extra virgin olive oil (, divided)

provolone cheese ((1 cup. I used deli slices and chopped))

shredded low-moisture mozzarella cheese ((1/2 cup))

finely shredded parmesan cheese ((slightly packed 1/2 cup))

canned artichoke hearts (, drained well and quartered (don't use marinated))

Red pepper flakes (, for serving (optional))