Yields: 60 hors d'oevre sandwiches

In a large heavy skillet cook the bacon over moderate heat, stirring, until it is crisp, transfer it to paper towels to drain, and chop it fine. In a bowl stir together the bacon, the mayonnaise, and the mustard. Spread the bacon mayonnaise on one side of each bread slice, sandwich the tomatoes between the slices, and cut each sandwich into 4 triangles.