For the Quick Bread:

1. Preheat the oven to 350°F and butter a 9 x 5-inch loaf pan. Place a piece of buttered parchment in the bottom.
2. Whisk together the dry ingredients until well mixed. Add the ½ cup of the chocolate chips and toss to coat in the flour mixture. Set aside.
3. Using an electric mixer, cream together the butter and sugars until light and fluffy. Add in the eggs and vanilla and beat well to combine. Add half of the milk and mix to combine. Add half of the dry ingredients and mix to just combine. Repeat with the remaining milk and dry ingredients, mixing until the batter is just combined and no dry bits remain.

For the Streusel:

1. Mix the ingredients for the streusel together until crumbly. I use a pastry cutter (or fork) to mix in the hard butter.

Assembly:

1. Pour the batter into the prepared pan and then top with the streusel. Bake for 1 hour (give or take, depending on your oven) or until a tester inserted into the middle of the loaf comes out clean.
2. Remove the pan from the oven and allow to cool in the pan for 20 minutes. Remove loaf from pan and finish cooling on a rack. Once cool, place the loaf on a heat-proof surface and top with the marshmallows and the remaining ¼ cup of chocolate chips. Using a kitchen torch, toast the marshmallows until golden and soft and the chocolate chips are melted. You could also place it under the broiler for 30 seconds or so, but watch it carefully. Slice and serve while the marshmallows and chocolate are still gooey. Reheat in the microwave or oven for a few minutes.