Little Workbench
The Little Workbench is a premade structure used to craft structures from recipes.
To craft a structure, simply use put a recipe in the first slot and press Craft. If you have the necessary materials, the structure will be outputted in the second slot. The source recipe will not be consumed.
If you want to put a interactive structure (a door or chair, for example) back into a Little Recipe all you need to do is put the structure in question in the first slot and a Little Recipe in the second and press Craft.