I’m a little obsessed with bean gratins. These cozy make-ahead suppers (or side dishes) are satisfying and economical, and they can take as little as twenty minutes to get into the oven. This Mediterranean-inspired version relies on a handful of ordinary ingredients—cooked beans (from scratch or a can), sautéed onions, sausage, canned tomatoes, and parsley—but somehow it all bakes up into one of those dishes that I can’t get enough of. It seems to get better with every bite, especially if that bite includes some of the crunchy bread crumb and cheese topping.
If I serve this as a main course, I include a vegetable on the side (like Broccoli Rabe with Garlic and Olive Oil, page 202, or Roasted Carrots, page 215). It also makes a hearty side for a juicy roast of lamb or beef, and it’s a good choice on a buffet because it holds up well and tastes just as good warm as hot. If you fall hard for this gratin, I encourage you to consider it as a starting point and use the guidelines in Bean Gratin Basics, page 130, to come up with your own combinations.
Get ahead: The gratin can be prepared through Step 4 up to 2 days ahead. Cover and refrigerate. Bake for an additional 20 minutes or so.