Well, I managed to get it to work. It seems BlankPlugin was never meant to be used as it is. You need to create at least a class derived from IModuleInterface that implements (may be empty) StartupModule and ShutdownModule and call IMPLEMENT_MODULE(FooPlugin, Module) in the .cpp
I followed the Stand Alone Plugin section of:
I attached a a plugin ready to be used. Just drop it in your plugins folder, rename the files that whatever you want and regenerate the project files (right-click .uproject and click o generae project files)
You should be ready to go.