Spread the bread with the butter and with a 2-inch scalloped cutter cut into 12 rounds. Arrange the salami, the cheese, and the bell pepper decoratively on the bread, spoon small dollops of the mustard onto the canapes, and press the onions into the mustard. The canapes may be made 30 minutes in advance and kept covered and chilled. Arrange the canapes on a platter.
Recipe Courtesy of Gourmet Magazine