Method:
Preheat oven to 350°F. Butter a 9-inch round pan and set it aside. In a large bowl, whisk together flour, 1/3 cup sugar, baking soda, salt and baking powder. Work 6 tablespoons chilled butter into flour mixture with your fingers until it resembles small pebbles; stir in chocolate chips. Stir in yogurt until just combined, and then knead in the bowl just until a dough forms.
Shape into a 6- or 7-inch imperfect loaf, transfer to prepared pan and bake until cooked through and golden brown, about 50 minutes. Set aside to let cool. In a medium bowl, use a fork to mash together remaining 6 tablespoons softened butter, raspberries and remaining 1 1/2 tablespoons sugar. Spread onto slices of bread and serve.