Granny's cornbread stuck for 30 years and the fix was 10 minutes of heat
My grandma always greased her skillet with cold shortening and her cornbread ripped every single time. Last month I preheated my 10 inch Wagner in the oven at 425 for 10 minutes, dropped in a spoon of bacon grease, and the loaf slid out clean on the first try. What temp and fat combo are you all using?
Did you let that bacon grease get hot in the skillet before the batter went in? That was the missing piece for me. I used to pull the pan out, wipe it with shortening, pour the batter, and back in the oven it went. Every time it stuck, even with a well seasoned pan. Now I put the fat in the pan and let it sit in that 425 oven until it just starts to smoke, maybe 8 to 10 minutes, then swirl it and pour. The batter sizzles on contact and you get that crisp edge that releases on its own. Bacon grease is my go to but lard works about the same if that's what you have.