Potato and Onion Gratin with Allioli

You don’t have to be Catalan to agree that pretty much everything tastes better with allioli, the bold, garlicky mayonnaise that brings to life so many of the region’s dishes. Patatas panaderas (the classic Spanish baked sliced potatoes) are great on their own. But add a cup of allioli and you’ve got a treat. Serve the potatoes with simple roasts that could use a garlicky kick or with saucy dishes, such as Seafood Stew in Romesco Sauce