Roast Beef and Cheddar Panini

The panini press turned into a diner-counter fixture across the U.S. in the 1990s, but the combination pressed inside it — sliced roast beef, sharp cheddar, and something creamy with a bite — goes back much further, to the classic deli steak sandwich shops of the Northeast built their reputations on. Roast beef and cheddar is a natural pairing: the cheese's tang cuts through the richness of the beef, while a swipe of horseradish mayo adds the same peppery lift you'd get from a jus or au jus dip, without the mess of a dunk sandwich. Caramelizing the onions low and slow is what elevates this from a quick lunch to something worth savoring — the sugars in the onion break down into a deep, almost jammy sweetness that balances the horseradish's sharp edge. Sourdough is the unsung hero here: its natural tang and sturdy crumb hold up to the press without turning soggy, and it crisps into shards of golden crust that shatter satisfyingly with the first bite. This sandwich shows up constantly in American lunch counters and home kitchens alike because it hits every craving at once — savory, tangy, sweet, and crunchy — in under half an hour, making it a reliable answer to the eternal weeknight question of what to make with deli meat in the fridge and a block of cheddar going soft.