For the doughnuts:
For the filling:
1. Place all doughnut ingredients, except the butter, into the bowl of a stand mixer fitted with the dough hook. Work on a low speed for about 4 minutes, or until well-combined and elastic.
2. With the mixer still running, add the butter piece by piece, until it’s all worked in and incorporated. There should be no visible pieces. This will take about 5-8 minutes.
3. Scrape down the sides of the bowl, cover with plastic wrap and set aside in a warm place to rise until doubled in size.
4. While the dough is rising, make the filling. Place the cream, milk, vanilla and gingerbread-spice mixture into a small saucepan over medium heat.
5. In a small bowl, whisk together the egg yolks, sugar and cornstarch. When the milk begins to bubble around the edges, remove it from the heat and slowly whisk it into the egg mixture.
6. Pour the mixture back into the pan over medium heat, whisking constantly. Cook until it boils and becomes very thick, about 1-2 minutes. Once the mixture is the consistency of soft butter, scrape it out into a bowl, cover and set aside to cool completely.
7. When the dough has risen, punch it down and scrape it out onto a well-floured surface. Make sure your hands are properly floured and pat the dough into a rectangle, about ½-inch thick, and cut out nine doughnuts using a well-floured 2.5-inch round biscuit cutter or large glass. Place the doughnuts on a lined baking sheet, cover with plastic wrap and set aside to rise for 45 minutes, or until puffy.
8. When the doughnuts are finished their second rise, place about 2 inches of oil into a high-sided pan (or use a deep fryer) and heat over a low flame, until it reaches 350 degrees (or until a small piece of dough dropped in the oil bubbles and rises to the surface).
9. Fry the doughnuts a few at a time (don’t crowd the pan) for about 1 minute each side, or until golden brown and cooked through.
10. Drain on paper towels and toss in the ½ cup sugar.
11. To fill the doughnuts, I use a flavor injector, like you would use for a turkey. I find this the easiest way to get the cream in. Alternatively, you can place the mixture into a piping bag fitted with a ¼-inch nozzle. Press the piping bag into the side of each doughnut and squeeze until you can feel the weight of the doughnut increase slightly.