For the pecan praline: Cover a workspace in parchment paper. In a heavy-bottomed saucepan, combine the light brown sugar, heavy cream, butter and water. Heat over medium-high heat, stirring constantly, until the praline mixture registers 240 degrees F on a candy thermometer. Add the pecans and remove from the heat, stirring vigorously with a wooden spoon until the candy mixture cools. Spread on the parchment paper and cool completely, then cut the pralines into small pieces.
For the basic custard: Combine the egg yolks, sugar and cornstarch in a small bowl. Bring the cream and milk to a boil in a small saucepan, then pour over the yolk mixture and mix until well combined. Return the mixture to the saucepan and cook until it coats the back of the spoon. Strain the custard through a fine-mesh sieve and refrigerate, with plastic wrap pressed directly against its surface, for 30 minutes.
For the chocolate pastry cream: Soak the gelatin in cold water until softened, about 5 minutes, then drain all excess water. Add the gelatin to 1 1/4 cups basic custard followed by the melted white chocolate; mix until well combined. (Save the remaining custard for another use.) Place the chocolate pastry cream in the refrigerator, covered in plastic wrap, until ready to use.
For the applewood-smoked bacon: Preheat the oven to 350 degrees F. Arrange the bacon on a baking sheet and bake until crispy, 8 to 10 minutes. Crumble the bacon.
For the doughnuts: Using a stand mixer fitted with the dough hook, mix together the flour, milk, sugar, yeast, salt and egg on low speed until you get a smooth dough, then increase the speed and add cold butter in stages. Mix until all the butter has been incorporated into the dough, and the dough is smooth and elastic. Remove the dough from the bowl and form into a ball. Wrap tightly in plastic wrap and refrigerate for 3 hours.
Line a baking sheet with parchment paper and set aside. Remove the dough from the refrigerator, roll out on a floured surface with a floured rolling pin to 3/4-inch thick, and cut out 12 rounds with a 3-inch round cutter. Arrange the dough rounds 2 1/2-inches away from each other on the prepared baking sheet and let sit at room temperature until doubled in size, about 1 hour 30 minutes.
Line a baking sheet with paper towels and set aside. Heat about 2 1/2 inches oil in a Dutch oven to 350 degrees F, then fry the doughnuts in batches until golden brown, 45 seconds on each side. Place on the prepared baking sheet and let cool completely.
For the sugar glaze: Mix the confectioners' sugar, salt and water until the consistency is thick and fluid (add extra water if needed).
Fill a piping bag with the chocolate cream. Pierce a small opening on the bottom of each doughnut and fill with the chocolate cream. Dip the doughnuts in the sugar glaze, sprinkle with chopped pralines and stick on small shards of crispy bacon.