If you don't have (or can't spare) a cast-iron skillet, sauté the apples and onions in any heavy skillet and transfer to a buttered 8x8" glass dish for...
Feta and bread get roasted alongside squash, then tossed with pleasantly bitter greens for a vegetarian dinner salad that's equal parts warm and cold,...
When working with a large quantity of greens, it's much easier to sauté them if they're blanched first. Their time in the olive oil is more for flavoring...