Easy Cream Puffs

Whisk 4 large egg yolks in a bowl until smooth.
Heat 500 ml heavy cream with 100 g granulated sugar in a saucepan over medium heat until warm, and the sugar dissolves.
Gradually add some warm cream to the egg yolks while whisking, then return everything to the saucepan and cook on low heat, stirring constantly, until thickened.
Transfer the pastry cream to a bowl set over ice-cold water, cover with plastic wrap, let it cool, and refrigerate for 1 hour.
In a saucepan, bring 240 ml water, 110 g unsalted butter , ½ tsp salt, and 1½ tbsp granulated sugar to a boil.
Remove from heat, add 120 g all-purpose flour, and stir until combined, then return to low-medium heat and cook for 2 minutes until the dough forms a ball and pulls away from the sides.
Transfer the dough to a bowl, let it cool slightly, then add 3 large eggs one at a time, mixing well after each addition until smooth and glossy.
Pipe the dough onto a lined baking tray, smooth the tops with a damp finger, and brush with egg wash made from 1 large egg and 10 ml milk.
Bake in a preheated oven at 375°F / 190°C (340°F convection / 170°C fan) for 25 minutes until golden and puffed, without opening the oven.
Let the shells cool completely on a wire rack.
Stir the chilled pastry cream until smooth, transfer to a piping bag, and let it sit at room temperature for 30 minutes.
Cut the cream puffs, fill with pastry cream, and finish with powdered sugar before serving.