@kaovalin : You could solve your problem with a supplier pipe. Have the pipe keep one stack of each ingredient in the cake-assembler and its inventory won't clog. The ingredients would then be stored elsewhere (e.g. the flour in the output slot of the ca making it) and provided by provider pipes. As an aditional bonus you will have access to the ingredients for other purposes (e.g. the sugar canes for making paper)
Or translocatorsor you could use a golem to keep it filled.
The possibilities are endless!