Combine first 5 ingredients in bowl. Combine milk and cream in medium saucepan. Add dry ingredients; whisk until well blended. Cook and stir on medium heat until mixture reaches 165°F.

Place melted chocolate in large bowl. Add milk mixture, stirring to combine. Strain mixture. Pour small amounts of mixture into blender and process 30 seconds. Continue until all of mixture has been processed. Transfer to clean bowl and chill over an ice bath. Refrigerate overnight.

Freeze mixture in ice cream maker according to manufacturer's directions. Spoon prepared ice cream into freezer container. Gently fold in OREO Pieces. Freeze until very firm.

Use #16 scoop to portion 2 scoops (5.5 oz.) OREO ice cream into pint glass. Slowly pour 5 oz. beer over ice cream. Serve with a straw and long spoon. (Keep remaining ice cream frozen to use for other servings.)