For 4 burgers:
1 1/2 lbs. lean ground sirloin
1/2 teaspoon EACH salt and pepper
1 1/2 teaspoons herbs de Provence
1 loaf French bread
Grey Poupon mustard
4 slices Gruyere cheese
4 tomato slices
Place sirloin in a medium bowl. Add salt, pepper and herbs. Mix with hands and form into 4 burgers. Grill or fry in a pan until done.
Meanwhile, preheat oven to broil. Cut 4 burger-sized pieces of French bread, and slice horizontally. Butter one half, and spread mustard on the other half, topped with a slice of cheese. Broil until golden brown.
Assemble burgers and top with a slice of tomato.