Lea's Tempura Batter Mix

1 box (40 oz) Bisquick

1 pkg (10 oz) potato starch (might be labeled "katakuriko")

1 box (1 lb) cornstarch

Combine all ingredients in a large bowl. Store in refrigerator. When ready to use, combine (only the amount needed) with cold water until desired consistency is reached. Fry between 350-375 degrees until golden brown.