The B50 Burger is a gigantic grease bomb, topped with Swiss cheese, a fried egg, a slice of tomato, and aioli that makes the whole thing slide out of its bun as soon as you try to pick it up. The first bite tastes like smoke and fat. It slithers down into your gullet and sits there. Heavily. Three bites would be more than enough. Half a pound is cruel.
The good news is Chef Leonard's all-beef burgers are probably better than Chef's Salisbury steak. The condiments taste fresh and the meat is juicy.
The bad news is Chef Leonard cannot prepare fries, the burger's natural companion. Even the duck-fat version comes to the table soggy and also cold. We shall not speak of the regular "bistro" kind. (They did come with a bright, flavorful ketchup, though, so there is that.) Service is friendly, but sometimes absentminded, and there seems to be an assumption that everyone is a tourist. Though, given the location, a block east of Michigan Avenue, that might be an accurate one. Locals should know better.
Chef's Burger Bistro, 164 E. Grand, 312-374-3092, chefsburgerbistro.com.