Heat milk in large pan to 120°F. Add popcorn; remove from heat. Let stand 30 min. Strain, pressing as much milk as possible out of popcorn. Discard popcorn. Combine milk and cream in same pan. Whisk in combined sugar, dextrose, dry milk and stabilizer. Cook on medium heat until mixture reaches 165°F, stirring occasionally.
Blend milk mixture, in small batches, in blender 30 seconds. Pour into medium bowl. Chill bowl over ice water bath until mixture is cold. Refrigerate overnight.
Place half sheet pan in freezer. Freeze milk mixture in ice cream maker according to manufacturer's directions. Cover bottom of frozen sheet pan with parchment paper. Spread frozen ice cream evenly into pan. Freeze until solid or overnight. Use 2-1/2-inch round cutter to cut out 17 ice cream circles. Keep frozen until ready to assemble.
For each serving: Place 1 ice cream circle between 2 OREO Wafers. Press 1/2 oz. bitz onto edge of sandwich. Freeze until ready to serve.