Update: I thought my grandma's cast iron cornbread trick was just old person superstition
She always said to put the skillet in the oven while it heats and pour the batter in when it's screaming hot. I figured it was just her being stubborn, so I used a cold pan for years and got cornbread that stuck and came out flat. Two Saturdays back I finally did it her way with my $12 Lodge pan, and the edges came out crispy with that little crunch all around. The batter actually sizzled when it hit the pan, and it slid out clean in one piece. Anyone know if this trick works the same for a glass baking dish or do I just need to buy a second skillet?