Preheat the oven to 450 degrees.
Lay slices of the bread, butter side down, on an ungreased sheet pan. Sprinkle evenly with the chopped chocolate, covering the bread to within 1/4-inch of the crust. Cover each with a second slice of bread, butter side up. Press closed with the back of a spatula. Bake until the bread is golden and the chocolate begins to melt, about 5 to 7 minutes. Using a spatula, carefully turn each sandwich over and bake 5 to 7 minutes more. Let cool slightly before serving.
Courtesy Gale Gand, Butter Sugar Flour Eggs by Gale Gand, Rick Tramonto, Julia Moskin, Clarkson N. Potter Publishers, 1999
Recipe courtesy of Rachael Ray