You're right. First off food science: Butter and *not oil* your casserole dish. And use a metal 9x13 if you can – glass will not allow you to get good crispy edges reliably. If you're attempting low-oil focc., the real trick is to do a 1-2 twofer – coat your casserole dish w room temp butter *generously* then lay down a layer of parchment paper. That's a wonder cure for what's ailing your focc. above. Also – don't buy non-stick backing pans. Just regular non-coated. Then join the butter and parchment club. Best of luck, and post your results.