Blintzes: Blend all ingredients, except butter, in blender until smooth. Cover. Refrigerate 1 hour.
To prepare blintzes, heat 9-inch nonstick pan on medium heat. For each blintz, pour 2 oz. batter into pan, swirling to spread evenly. Cook 1 min.; turn over and cook 1 additional min. Remove from pan and cool on parchment paper-lined sheet pan. Cover with second piece of parchment until ready to assemble. Repeat with remaining batter.
Cream Cheese Sauce: Whisk all ingredients until smooth and well blended. Spoon into pastry bag fitted with a small plain tip. Refrigerate until ready to use, or up to 4 hours.
OREO Blintz Filling: Combine all ingredients, except cookie pieces, until well blended. Fold in cookies.
Assembly: Preheat standard oven to 400°F. Place one #40 scoop Filling on lower third of each Blintz. Fold bottom edge up and over Filling. Fold in sides and roll up to form a "package", ending with seam-side down. Place on parchment paper-lined sheet pan. Repeat with remaining Blintzes and Filling.
For each serving, heat an ovenproof skillet on medium heat. Brush with melted butter. Add 3 filled blintzes. Cook 2 min. on each side or until crisp. Transfer skillet to oven.
Bake 10 to 12 min. or until internal temperature registers 160°F and Filling is set. Transfer blintzes to serving plate. Drizzle with 3 Tbsp. Cream Cheese Sauce.