I wanted to try this caramelized onion cookie recipe i found:

https://littlebittybakes.wordpress.com/2012/01/26/caramelized-onion-shortbread-cookies/

But i also want to turn them into "buttons", as with this recipe:

https://www.smartschoolhouse.com/easy-recipe/button-cookies

Which is the reason i entitled this post "how do i make shortbread a bit less crumbly / more elastic?"

Because button-holes are less prone to break in an elasticky-firmer cookie, than a crumbly cookie. In other words, how do i strike a balance so that its just firm enough so they'll hold the button-shape, yet not so firm that its overly-tough to eat?