1 For crust, thaw pastry according to package directions. On a lightly floured surface roll pastry to a 12-inch square; cut out a 12-inch circle of pastry. Place pastry circle on a large baking sheet or a 12-inch pizza pan; generously prick bottom. Bake in a 375° oven 15 to 18 minutes or until golden brown. Cool.
2 In a large mixing bowl combine greens, artichoke hearts, tomatoes, and olives. In a small mixing bowl stir together semisoft cheese or cream cheese, mustard, and enough milk to make of drizzling consistency; drizzle over greens mixture. Toss to coat well.
3 Preheat broiler. Sprinkle 1 cup of the mozzarella cheese evenly over crust. Broil 3 inches from heat for 1 to 1 1/2 minutes or until cheese is melted. Spoon salad mixture evenly over cheese. Sprinkle remaining mozzarella cheese on top. Broil for 1 to 2 minutes more or just until cheese starts to melt. If desired, arrange avocado slices on top. Cut pizza into wedges.