Doamayger-D

Daijirou Kyogyoku is the 15th generational proprietor of the Amashodo sweets shop in Kyoto. One day, after falling down the steps into the basement, Daijirou finds a hidden door, behind which is a giant hangar housing a mecha named Doamaiger D. At the same time, people start getting turned into giant mecha/kaiju monsters called Mekaiju, and the only way to return them to normal is for Daijirou to prepare & feed them sweets made via Doamaiger. While fighting off each successive Mekaiju, however, Daijirou will also find out who's behind the creation of these monsters, learn the about the origin of his robot, & take on Mr. Robert, an American sweets magnate who uses his own giant robot to automatize sweets production.

Super sadly this is the only one of its kind