Filling
3 large sweet potatoes
1 ½ cups brown sugar
½ teaspoon crushed cardamom seeds
Dough
1 ½ cups all-purpose flour
1 ½ cups whole-wheat flour
¼ teaspoon salt
1 tablespoon oil plus 1 tablespoon oil
1 ½ cups water
Preheat oven to 375 deg. Wash sweet potatoes and wrap individually in aluminum foil. Place them on a baking sheet and bake for an hour. (During this hour you can make the dough). Cool the potatoes. Scoop the insides of the potatoes into a non-stick or thick bottom wide pan and mash. Discard the skin. Mix in the brown sugar. Cook on medium low heat mixing until the sweet potato mixture becomes thick. Add cardamom powder and mix. Transfer to a plate and cool completely. Once cooled, roll potato mixture into golf size balls.
Dough:
In a medium bowl, mix all-purpose flour, whole-wheat flour, salt, and one tablespoon of oil. Add water and make soft dough. (The dough should be little softer than chapathi dough). Pour one tablespoon of oil in the bowl and coat the dough with oil. Keep it covered for ten minutes or until ready to use.
Make dough into same number and same size of balls as sweet potato mixture and flatten each one. Fold the dough around the sweet potato balls and close. Repeat until all the sweet potatoes and the dough have been used.
Heat a griddle on medium low heat. Take a banana leaf or a 5-inch square of parchment paper. Smear some oil on the leaf or paper and place a dough and sweet potato ball and flatten it with oily fingers. Transfer the flattened poli (bobbattu) onto the griddle gently and roast it until it becomes light brown on both sides. Place the first sweet potato poli on a paper towel lined plate to absorb moisture in between the plate and poli. Put a small piece of parchment paper in between each poli to prevent them from sticking on rest of the polies.
Makes about 20 polies (bobbatlu).