This is my favorite twice-baked potato recipe by far. The original came from Great Greens by Georgeanne Brennan. The book has some great photography (by Frankie Frankeny), good enough to make you want to eat your vegetables. The first part of the book is a comprehensive guide to everything green, giving information on nutrition, preparation, gardening and storing.
Then come the recipes. Chard and Lentil Soup with Duck Confit. Yes, please. Gratin of Belgian Endive with Pancetta. Don't mind if I do. Don't worry, there are plenty of vegetarian recipes too, like this one.
Coat your potatoes in olive oil, then bake for about an hour at 400, depending on size. The skins will get shiny and crinkly, which helps them hold up to stuffing and more baking. Let cool so you don't burn your fingers, then cut in half, and scoop out the insides to form a shell for stuffing.
While the potatoes are baking, wilt chopped escarole (tough stems and darkest outer leaves removed) in butter, covered. Add a little chicken broth, cover, and braise for a bit. Remove the cover and raise the heat a little until most of the liquid is evaporated.
Mix the scooped-out potato with cubed Gruyere, the braised escarole (drained), ground pepper and a little salt. Careful on the salt, 'cause there's cheese. Top with a little grated Gruyere, and bake for about 30 minutes.
These make a great side dish, but I usually have a couple halves by themselves for dinner (doused in hot sauce, of course).