Place the bread flour in a large mixing bowl and make a well in the center. Add the milk and honey to the well, then sprinkle the yeast on top and allow it to dissolve (approx. 5 minutes).
Stir the dough together on medium-low speed.
Stir in the olive oil, then the heavy cream until incorporated.
Stir in the eggs, one at a time, allowing each egg to fully incorporate before adding the next.
Add the orange zest, salt, vanilla, and raisins/pine nuts (if using), and knead the dough for at least 10 full minutes to develop the glutens and encourage elasticity.
Cover the bowl with plastic wrap and allow the dough to rest in a warm place for one hour, or refrigerate it overnight.
Punch down the dough and divide it into 12 equal portions.
Roll each portion into a tight ball, then place on parchment-lined baking sheets.
Mist a sheet of plastic wrap with non-stick spray, then lay it lightly over the dough balls.
Allow the unbaked buns to rest in a warm place for one hour.
Preheat the oven to 350 degrees F.
Brush the buns with egg wash, then bake until puffed and golden (approx. 16 to 24 minutes).
Cool completely, then split horizontally and sandwich with filling.
Garnish with powdered sugar, if desired.