Haven't seen a post of this relatively recent ecchi manga about a demon lord(?) looking for a job at a family restaurant.
The demon lord(?) and her companion are both evidently loli characters who, after they are fed, both go through instantaneous transformations where they...well the images will explain better than words (they also spontaneously transform back into their beginning forms when they're hungry).
Images from chapter 1
Amon Patricia, Demon lord(?):
Nonko, the mushroom girl:
Amon Patricia, Demon lord(?) post-feeding:
Nonko, the mushroom girl post-feeding: