Preheat oven to 400 degrees. Line 12 cup standard muffin tin cups with paper liners. In a large bowl with a mixer, beat butter and sugar on medium high until light and fluffy, about 2 minutes. Add eggs, one at a time, beating well after each addition. With mixer on low, beat in flour and salt. Beat in chocolate until just combined.
Divide half the batter among cups, add two raspberries to each, and top with remaining batter. Bake until tops are just set and no longer shiny, 10 to 11 minutes, let cool in pan on a wire rack, 10 minutes. Remove from pans, dust with confectioners' sugar, and top with ice cream, if desired.