You’re low on flour, rice is scarce, and your pasta stash is down to one lonely box of elbows. Thank Heaven for potatoes. Especially when it’s easy to dress them up Greek-style—bright, pungent and with an aroma so intoxicating it could serve as stress-relief therapy. “Greek-style” is simply shorthand for “lemon, oregano and olive oil” (the way “Florentine” means spinach). But this is not your standard dish of crispy potato wedges done up Greek-style. Here, layers of thinly sliced potatoes roast and steam, soaking up caramelized lemon sauce and blissing out on oregano. Cut into the casserole and you’ll find strata of textures and flavors, from soft and creamy on the bottom to crispy…