Combine the water, milk, butter, salt and sugar in a saucepan and place over low heat until the butter is melted.
Once the butter is melted completely, turn the heat on high and bring to a boil.
The moment it comes to a boil, remove off heat and immediately add the flour, all at once. Mix well with a wooden spoon or spatula until the flour is well absorbed. Place the saucepan back over medium flame and continue cooking for 2-3 minutes, mixing all the time, until a layer of dough remains on the bottom of the pan - keep the flame on medium to avoid burning and mix all the time with the spatula or spoon to cook out the liquid.
Remove from heat and allow the dough to cool down for 10 minutes.
Start incorporating the eggs, one by one, mixing well after each addition. Add the last egg bit by bit to make sure you're not adding too much egg. The number of eggs used depends on the humidity of the dough, even on weather and the size of the eggs.
The dough is ready when it falls off the spoon and leaves a streak that doesn't collapse on itself if you run your finger through it.
Spoon the choux pastry in a pastry bag fitted with a round nozzle then pipe a small round of dough (measure a circle on the parchment paper before piping).
Bake in the preheated oven at 350F – 180C for 40 minutes more or less – or until golden brown and crisp.
When done, allow to cool down then cut in half, forming two discs.
Place aside.
Pastry cream:
Heat up the milk in a pot.
Mix the egg yolks, sugar and salt in a bowl. Add the cornstarch and mix well then pour the hot milk over the mixture.
Place back on heat and cook until thickened.
Bloom the gelatin in cold water for 10 minutes then melt it and stir it into the cream.
Place plastic wrap on the surface and allow to cool down completely.
Fold in the whipped cream and spoon the cream in a pastry bag fitted with a round nozzle.
Strawberry compote:
Combine the strawberries, half of the sugar and water in a saucepan.
Place over low heat and cook for 3-4 minutes.
In a small bowl, combine the remaining sugar and the pectin.
Stir it into the fruit mixture then continue cooking for another 3 minutes.
Remove from heat and stir in the lemon juice.
Allow to cool down in the pot.
To assemble the Paris-Brest:
Spoon the strawberry compote into the bottom half of the choux ring.
Spoon the pastry cream on top and finish off with a few strawberry slices.
Cover with the other half of choux pastry and decorate.