Preheat the oven to 350°F (180°C).

To make the choux pastry, add the water, butter, sugar, and salt to a saucepan. Bring to a boil. When it starts to bubble, add the flour all at once.

Stir the dough with a spatula until it dries out and pulls away from the sides of the pan. Remove from heat and let cool.

Once the dough has cooled slightly, beat the egg and add it to the pan. Continue mixing with the spatula until the dough is smooth and thick, then transfer it to a piping bag.

On a baking sheet lined with parchment paper (or a silicone baking mat), pipe a ring of dough. Sprinkle with sliced almonds and bake for 10 to 15 minutes without opening the oven door.

Meanwhile, make the cream.

Beat the egg yolk with the sugar until the mixture is pale and fluffy. Add the softened butter while continuing to beat. Finally, add the praline paste and mix until the cream is thick and smooth.

To assemble the Paris-Brest: Using a bread knife, slice the pastry ring in half horizontally. Fill with the praline cream. Dust with a little powdered sugar and chill until ready to serve.