Whisk water and bread flour together in a saucepan over low heat. Cook roux until an instant-read thermometer inserted into the center reads 150 degrees F (65 degrees C). Remove from heat and let cool to room temperature.
Place 3 cups plus 3 tablespoons bread flour, sugar, milk powder, yeast, and salt in the bowl of a stand mixer fitted with a dough hook. Mix on low speed. Add cooled roux, egg, cream, and water. Knead dough until it comes together in a shaggy mass, 1 to 2 minutes. Continue to mix on low speed until dough starts to leave the sides of the bowl.
Increase speed to medium and start adding butter. Mix until completely incorporated and dough is smooth, 10 to 20 minutes. Remove dough from the mixer and place in a greased bowl. Cover and let rise until doubled, about 40 minutes.
Flatten dough and roll into an oblong shape. Place in a greased loaf pan. Cover and let rise until doubled, 45 to 60 minutes.
Preheat the oven to 450 degrees F (230 degrees C).
Uncover loaf and bake in the preheated oven until golden brown, 30 to 35 minutes. Cover with foil if top starts to brown too quickly. Cool in the pan for 10 minutes before inverting onto a rack to cool completely.