“Ummm, use it as what it really is: Money”.
...ummm, I guess you’d just shave a sliver off of a 10oz bar for a loaf of bread? A little larger sliver for meat etc?
While it is possible to do exactly what you wrote, the better choice might be to fall back on having some smaller lumps of gold on hand. Think of all the benefits, not the least of which is; you will not have to run the risk of cutting your finger on a sharp knife.