Lightly spoon flour into a dry measuring cup; level with a knife. Combine flour, sugar, and salt in a medium microwave-safe bowl; gradually add 1 3/4 cups milk, stirring well with a whisk. Microwave at HIGH 4 to 5 minutes or until thick, stirring after every minute.
Combine 1/4 cup milk and egg substitute in a large bowl. Gently stir one-fourth of milk mixture into egg substitute mixture; add to remaining hot milk mixture. Microwave at HIGH 1 minute; stir well. Stir in vanilla. Pour into a bowl; cover surface of pudding with plastic wrap. Chill.