Pastry Cream:

• In a medium saucepan, combine ½ cup milk and 1 cup heavy cream. Heat over medium, stirring constantly until almost boiling (4-5 minutes). Remove from heat and stir in vanilla extract. Set aside.
• In a bowl, whisk together egg yolks until smooth. Add the remaining ½ cup milk to the egg yolks. Slowly sift in the flour and whisk until smooth.
• Add sugar to the egg mixture, then slowly pour in the hot milk, whisking constantly.
• Pour the mixture back into the saucepan and heat over medium, stirring constantly until it thickens and simmers (about 5-6 minutes). Remove from heat and add butter.
• Press plastic wrap directly on the pastry cream and refrigerate for 2-3 hours until cooled.

For the Donuts:

• Sift together bread flour, sugar, and yeast into a standing mixer bowl. Add butter, orange zest, vanilla extract, and eggs.
• With the dough hook attached, mix on low speed, adding the warmed milk gradually. Mix for 5 minutes until a smooth dough forms.
• Transfer dough to a greased bowl, cover with plastic wrap, and let rise for 1 ½ to 2 hours until doubled.
• Roll the dough to ½” thick and cut out 3-inch circles using a biscuit cutter. Place donuts on a parchment-lined tray to rise for 1-2 more hours.
• Heat vegetable oil in a Dutch oven to 350°F. Fry donuts in batches, 2-3 minutes per side until golden brown.
• Remove with a slotted spoon and drain on paper towels. Roll in granulated sugar while still warm.
• Fill a pastry bag with chilled pastry cream and pipe into each donut by piercing the side or cutting a small slit.