HPMC is used a lot in batters, as when mixed into cold water, it increases the batter viscosity and thus leads to better adhesion to the product. Then upon frying, the HPMC gels and thus forms a barrier to reduce both oil uptake and water migration.
Hydrate the HPMC in the water. Add the other dry ingredients and mix until homogeneous. Roll the meat or vegetable in the batter. Roll in breadcrumbs if desired.