I used a thing from Pampered Chef called the Cut-n-Seal. My mom gave it to me years ago so I don't know if they still make them. This looks like it does the same thing, though.
Just as a heads up, they are pretty greasy. Next time I make them I'm going to cook them on a rack (like this one: https://www.amazon.com/dp/B01N693H66/ref=cm_sw_r_cp_apa_fabc_9HT8M34S49449JQZ93MC) so the grease can drop down and not get soaked up.
I’ve had no issues with it….and I have issues with all shakes.
Here’s a link to it on Amazon.