"One of the best recipes he developed was this German apple pancake"
Um, can you word it a little different so it doesn't sound like you guys are claiming you came up with the idea of a German apple pancake? Like "his take on the German..." or "this take on..."
I'm admittedly a bit protective of the idea of German apple pancakes/"Dutch babies" - it's been a family favorite for most of my life (I literally got a copy of a cookbook specifically so I'd have the cookbook my mom got her recipe for it from). Most people I run into have no clue what a German apple pancake is, but they're super delicious and I've brought the idea of them to kitchens when I worked as a cook.
An oversimplification is that they're kind of like giant popovers with apple pie filling. I sometimes make them savory (such as adding in sausage and onion when I sautee the apples).