Using 2-3/4-inch round cookie cutter, trace 32 circles on parchment paper, spaced 1- inch apart, to create templates for piping churros.
Combine ice cream and 5 oz. OREO Pieces. Freeze at least 2 hours or until firm enough to scoop. Portion 16 ice cream balls using #16 scoop; flatten slightly. Freeze on sheet pan until ready to use.
Meanwhile, bring water, butter, 1/2 oz. sugar and salt to boil in saucepan. Add flour all at once, stirring with wooden spoon until mixture forms a ball. Remove from heat. Gradually add eggs, mixing until incorporated after each addition. Stir in remaining 2.75 oz. OREO Pieces just until combined. Spoon batter into pastry bag fitted with 3/8-inch plain tip.
Beginning at center of circle template, pipe a spiral of batter to fill each circle. Carefully slide off 1 churro at a time into 350°F deep fryer. Cook until golden brown on both sides. Remove with slotted spoon or spider; drain well. Sprinkle with 2 tsp. sugar; keep warm. Repeat with remaining batter circles.
When ready to serve, place 1 ice cream portion on flat side of 1 churro. Top with second churro to create sandwich.