Chicago abounds with intellectual and expensive dining experiences, but ask yourself, comrade: Is this the food that fortifies your soul? Now consider the patty melt at this octogenarian diner: griddled freshly ground round, sharp American cheese, and silky grilled onions sandwiched between slices of crisp rye. It’s straightforward, it’s cheap – and it’s the kind of dish that warms something profound in you. $8.52. 2116 W. 95th St., Beverly