Prepare Cherry Jam: Cook the cherries and sugar over medium heat, stirring occasionally, until the mixture thickens and becomes glossy. Cool it in the fridge overnight to enhance the flavor.

Make Crème Pâtissière: Heat the milk and half the sugar in a saucepan. In a separate bowl, whisk together the eggs and remaining sugar. Gradually add the hot milk to the egg mixture, then return to the stove, cooking until thickened. Stir in the butter and chill in the fridge overnight.

Dough Preparation: In a stand mixer, combine all the dough ingredients. Mix until smooth, then knead the dough for about 5-7 minutes. Let it rise for 1 hour, or until it has doubled in size.

Fry Doughnuts: Roll out the risen dough on a floured surface. Cut it into rounds, then heat oil in a deep fryer or heavy pot. Fry the doughnuts for about 2 minutes on each side until golden brown. Drain and cool for 1 hour before filling.

Make Cherry Cream Filling: In a bowl, whip the cream until soft peaks form. Gently fold in the chilled crème pâtissière and softened cherry jam until well combined.

Fill Doughnuts: Using a piping bag, carefully fill each cooled doughnut with the cherry cream mixture, ensuring they are upright to avoid leaks.

Glaze Doughnuts: In a bowl, mix the sugar and water until smooth. Adjust the water for desired consistency, then dip or drizzle the glaze over filled doughnuts.

Optional: Dust with powdered sugar for an extra touch of sweetness.