In a small mixing bowl or measuring cup, add the yeast and ½ teaspoon sugar into the warm water. Briefly stir to combine and let stand for 5 minutes, or until the yeast becomes foamy.
Meanwhile, stir together the flour, remaining sugar, and salt in the bowl of a stand mixer.
Once the yeast is foamy, stir in the milk and egg. Pour the yeast mixture into the dry ingredients and stir until just combined and sticky. Using the dough hook, knead the dough on low speed until it just comes together. Add in the partially melted butter, a tablespoon at a time. Continue kneading the dough until it is smooth and elastic. Try to refrain from adding too much extra flour (a couple tablespoons is okay).
Lightly grease a mixing bowl and place the dough inside. Cover the bowl with plastic wrap or a clean kitchen towel and allow the dough to rest in a warm place until doubled in size, 60 to 90 minutes.
Once the dough doubles in size, punch it down and turn it out onto a lightly floured surface. Divide the dough into four equal portions and tuck them into round balls. Roll each portion of dough into a circle, 10 to 11-inches in diameter.
Place one of the dough circles on a piece of parchment paper. Dollop ¼ cup of raspberry pie filling on top and spread it out with an offset spatula. Carefully place the next dough circle on top and repeat. Continue with the remaining dough and filling, ending with a plain dough circle on top. Trim the edges as needed.
Using a 3-inch round cutter or the rim of a drinking glass, gently score the center of the circle. Next, cut the dough into 16 equal pieces (like a pizza), stopping at the scored circle in the center. Do not cut through the center of the circle.
Take two strips of dough (next to each other) - one in each hand. Twist the pieces away from each other 1 ½ times around. Bring the ends together and pinch to create a point. Continue around the circle until you have 8 points.
Cover the dough with plastic wrap or a clean kitchen towel for 20 to 25 minutes, or until slightly puffed (it will not double in size). Meanwhile, preheat the oven to 350°F.
Slide the star bread (still on the parchment paper) onto a baking sheet. Whisk together the egg white and cream to make an egg wash. Brush the egg wash over the star bread and bake for about 25 minutes. When done, the bread will be light golden brown with an internal temperature of 190°F. Allow the bread to cool as you make the glaze.
Stir together the confectioners’ sugar, vanilla, and milk to create a pourable glaze. Drizzle the glaze over the partially cooled star bread.
The star bread is best enjoyed on the same day as it is made. Cover leftovers with plastic wrap at room temperature for up to 2 days.