Perfect Burgers

Silverton says burgers are the perfect party food because the toppings can be done in advance, then guests use them to personalize their burgers. Though she offers three cheeses, she says that from experience, most takers are for Gruyère, 25% might take cheddar and one of a group will want blue. Crumble out enough blue to look pretty in a bowl, 2 to 3 ounces, and know it may go into salad dressing for the next meal. Ditto cheddar, but this may fill an omelet. The cheeses should be good-quality, such as Point Reyes Blue, aged Gruyère and Grafton cheddar from Vermont or Fiscalini or Straus cheddar from California. The buns should be good-quality soft sesame or poppy seed hamburger buns. For the beef, ask the butcher to grind 2¾ pounds of prime chuck (10% to 15% fat) with 4 to 6 ounces of prime sirloin fat (the combination should have 20% to 28% fat total).