At work, sometimes the easiest way to take notes is on good, old fashioned pen and paper. At times, I find myself trying to find a note I'd written in the past. Here's a clever way to use hashtags on a physical notebook.
Now you'd go back to the first page where the recipe is and on the exact same line as the 'Chinese' label you just wrote you'd make a little mark on the right edge.
You'd make this mark so that even when the notepad was closed the mark would be visible. After repeating this for various recipes you'd now have various tags visible on the notebooks edge.
Now if you ever wanted to find a Chinese recipe you'd simply look at the index, locate the Chinese recipes label and look along the visible edge to find every single page which has been tagged as Chinese. Then it's simply a case of flicking to each page.