Position oven rack in bottom slot in oven. Heat oven to 375 degrees F.
Knead 2 teaspoons oregano into dough. Roll out on floured surface to 14-inch circle. Fit into 9-inch springform pan.
Mix remaining oregano, artichoke, oil, vinegar, salt, pepper, garlic, egg and crumbs in processor or blender until smooth.
Sprinkle half of spinach into pan. Top with half the salami. Mix cheeses; sprinkle third over salami. Top with 1 jar peppers. Top with half of artichoke mixture. Repeat layering. Top with remaining cheese. Fold dough edges over top.
Bake on bottom rack in 375 degree F oven 1 hour, until instant-read thermometer inserted into center registers 140 degrees F. If cheese browns too quickly, tent with foil. Cool on rack. Refrigerate 2 hours or until firm.
Remove side. Cut in wedges. Makes 16 servings.