Peel onions and "wedge" (actually slice into 6ths or eighths). Saute in batches in olive oil (a couple of tablespoons per batch of onion) until translucent slightly browned. Drain the cooked onion in a colander set in a bowl, reserving the liquid in bowl for use.
Drain & Slice the olives in thirds or quarters. You can use the whole cans, but usually 3/4 is enough. Drain and mince the anchovies.
Using a jelly roll pan, spread out first layer of pizza crust, drizzle alittle of the onion oil and juice onto it and spread. Spread all onions on crust. and top with your sliced olives, then sprinkle the minced anchovy all over. (be sure not to group too much anchovy in one area, you want little pieces distributed throughout, but no big chunks.
Cover with second crust folding over sides and sealing. Cut several small steam holes & Bake in pre-heated 425 degree oven for approx. 45 min.- 1hr till golden brown. Leave in pan and cool and rest for 8 hours or overnight. Cut& serve at room temp.