The Combat Baker and Automaton Waitress: Volume 1 by SOW

The war hero known as Silver Wolf - Lud Langart - piloted a humanoid assault weapon while dreaming of life as a baker. After the war, Lud now peacefully runs a bakery, but, thanks to his frightening scowl, he can't sell a single loaf of bread. After posting an ad for a waitress in a last-ditch effort to save his business, who should reply but a beautiful, silver-haired, red-eyed young girl. What Lud doesn't know is that this new waitress was born from Avei, his AI partner installed in the weapon he piloted during the war.