In a small bowl mix together the milk and 1½ teaspoons of sugar, sprinkle the yeast on top and let sit for 10 minutes, then mix together.
In the stand mixer add the flour, zest, remaining sugar, salt, egg, vanilla and yeast mixture, knead on low speed then increase the speed and knead for up to 7 minutes.
Add the butter and knead again for approximately 10-15 minutes, until the dough stops sticking to the side of the bowl and is soft, smooth and elastic.
Scrape the dough into a lightly buttered bowl to rise in a warm draft free area for approximately 2 hours or until doubled in bulk.
Transfer the dough to a lightly floured flat surface, divide into 6 parts and shape into a slightly oval shape. Place the buns on a parchment paper lined baked sheet, cover and let rise in a warm draft free area until doubled, approximately 1½ hours.
Pre-heat the oven to 350F/180C.
Brush the buns with the egg wash and bake for 18-20 minutes or until golden brown and baked through. Remove from the oven, move immediately to a wire rack to cool completely.
Brush the completely cooled buns with the sugar syrup, cut each bun on a slight angle be careful not to cut all the way through, fill the open area with whipped cream.
Dust with powdered sugar and serve immediately. Enjoy!
FOR THE EGG WASH
In a small bowl, beat together the egg and milk until combined well.
FOR THE CREAM FILLING
In a large bowl whip the cream until soft peaks appear then add the powdered sugar and continue to beat until thick peaks appear.
Notes
The dough can also be left to rise overnight in the fridge.
Storage
Once the maritozzi are filled with cream, they should be served and eaten immediately. Plan on making them and enjoying them the same day!
