Grind all these together by adding water.
Pour half of the dough to a vessel and warm the remaining half in a pan
Keep stirring while warming as the dough gets thick very quickly
Once the dough thickens, switch off the fire, grind the warmed portion again by adding little water to make a smooth form.
Mix this along with the first half kept aside
Keep it overnight, and thus the dough is ready for palappam...make the consistency of the dough accordingly by adding water.
For vellayappam, i suggest not to go for the warming process , coz it makes the appam too soft. So you can just grind the above ingredients and keep it overnight as such.