You tried and on your other cast iron stuff I know you said they are rusted butyou can scrub them and reseason them and still use them that's what's great about cast iron
Don't let it get wet for long and dry it good. Season it with oil every time you use it just like you do your Blackstone! You got this. Cast iron heats evenly. I use cast iron to make cookies in the oven, 20 minutes at 400, perfect everytime!
I'll bet that it *might* work if you set the skillet on a metal cooling rack, so that the skillet doesn't rest directly on the Blackstone. And oil or shortening might work better to grease the pan, because butter tends to burn more readily than either of those.
Put the temperature u would the stove in the house. Butter is why it's burnt. Just use a touch of flower next time but if the pan is seasoned correctly, it won't stick xo
I would put a cast iron trivet on the Blackstone and then the pan on top to prevent the burning. I wouldn’t place the cast-iron directly on the Blackstone.
Preheat your oven to around 500°F clean Rusty cast iron with vinegar spread a thin coat of bacon fat or real butter all over and bake it on repeat the process several times and it will give you the hard smooth black coating do not use soap after you have treated them just rinse them with hot water it should just rinse off if you seasoned them correctly