Cornbread Gratin with Sweet Potatoes and Summer Squash

Summer and Fall remain fused together here in the desert, and so for this delectable gratin I melded my seasonal vegetables, too. I find gluten free cornbread sours quickly (so strange -- any ideas on why?), so this is perfect for the last third of the pan.

Three yellow summer squash
Three medium sweet potatoes
1/3 pan of cornbread, torn into hunks and crumbs...probably 2 1/2 cups
Several cloves of garlic, minced
Feta
Olive oil
Butter
Fresh oregano (although dried will do)
Sea salt
Red pepper flakes, if you want some heat (I prefer all creamy mildness in this dish)

Slice summer squash and potatoes into thin rounds, unpeeled. Preheat oven to 400.

Toss sliced squash and sweet potatoes with lots o' olive oil, minced garlic, oregano, salt, and pepper if you prefer. Set aside.

Brown some butter in a frying pan. Add cornbread crumbs, wait until butter is absorbed, and remove.

Layer a baking pan with the dressed summer squash and sweet potatoes, and lots of crumbled feta. Top with cornbread. Bake for 30 minutes.