Place the butter, milk, water, and sugar in a saucepan over medium heat and bring to a boil, with a spatula, quickly stir in the flour over medium-low heat and stir constantly until the dough comes away from the sides of the pan and forms a smooth ball.
Transfer the dough to a large bowl, once the dough is warm beat on low speed for a minute to release the steam from the dough. Then start adding the eggs one by one and continue to mix until you have a smooth thick shiny paste. You will notice that the dough will separate and then come together. Continue to mix until you have a smooth thick paste.
Transfer the dough to a large piping bag. Pipe 1-inch thick ring of dough inside the 8 inches that is drawn on the parchment paper. Pipe another 1-inch thick ring inside the first ring, make sure the ring is touching. Pipe the final ring of dough on top, along with the center seam between the first two rings of dough.
Egg wash the pastry and sprinkle the almond flakes on top. Bake for 15 minutes and then reduce the oven temperature to 180 degrees, bake for another 40-45 minutes or until the choux pastry is a golden brown color, puffed, and crisp. Don’t open the oven door while the choux pastry bakes or it might deflate. Turn the oven off, leave the oven door slightly open, and leave the pastry in the oven so the shell can further dry out (about 30-minutes). Remove from oven and cool on a wire rack.
For Praline Paste: In a small saucepan heat sugar and water over medium-high heat until it turns golden brown. Add butter and mix well, then stir in nuts to coat with the caramel and transfer the praline to a baking sheet to cool completely.
Break the praline into smaller pieces.
Grind in a food processor until it gets into a thick paste, for about 10 minutes.
For Praline Cream: Whip the cream and icing sugar, when it forms soft peaks add in the praline paste and beat until thick. Don’t overbeat it.
Assembling: Cut the pastry in half and pipe the cream onto the pastry and close it. Sprinkle the powdered sugar and serve.