Begin by making the compote, add the strawberry jam and tablespoon of water to a small saucepan. Heat the jam until it forms a syrup and then add the chopped strawberries. Cook the compote for a couple of minutes allowing it to bubble, then leave it to cool.
To make the streusel combine the flour, sugar and fleur de sel in the bowl of a food mixer. Knead with the paddle attachment then add the softened butter.
Continue on a medium speed until the butter mixes with the dry ingredients to form a dough.
Roll out the pastry between two sheets of greaseproof paper to about 2mm thick, then place in the fridge or freezer.
When chilled use a pastry cutter to cut out 10 rounds of pastry 3cm in diameter, return to the fridge.
To make the choux pastry, preheat the oven to 180C (160C Fan) Gas 4 and line two baking trays with baking parchment.
Put the butter, salt, sugar and 120ml water in a medium pan over a medium-high heat. Once the butter has melted and the mixture is at a rolling boil, add the flour and quickly stir together with a wooden spoon until the mixture forms a dough.
With the pan still on the heat, stir vigorously for 2 minutes, then tip the dough into a bowl and beat for a few minutes until it stops steaming. These two actions help to cook the flour and dry out the dough, which in turn helps it to absorb more egg. This helps the choux pastry to expand properly as it bakes.
Add the eggs, one at a time, beating until fully absorbed before adding the next. Depending on the flour used and how much water evaporated as you made the dough, the choux pastry will need varying amounts of egg, so the above is given as a guide.
With this recipe I usually add two eggs and then very slowly start adding the remaining egg, checking the texture of the dough after each addition. You are looking for a dough that has a shine and when it is lifted from the bowl, it should fall from the spatula in a ribbon that forms a "V" shape. If the dough doesn't contain enough egg, it won't expand properly and will be prone to cracking as it bakes; if there is too much egg, the dough won't hold its shape and will collapse as it bakes.
To prevent the dough from drying out and forming a skin, immediately put the dough into a piping bag with a 1.5cm plain round piping tip fitted.
Pipe balls of choux onto the prepared baking sheets, ensure they are well spaced and around 3cm in size. You may find that you have more than 10 choux buns, but just keep piping them - don't pipe on top of the existing buns as the shape will distort. If you have extra choux buns they freeze well once cooked.
Top each choux bun with a streusel round and bake for 25-30 minutes until golden brown and crisp. Turn off the oven and leave in the oven to cool for 30 minutes before filling and decorating.
When the choux has cooled down, gently slice the tops off the choux buns, just below the disc of streusel pastry.
Whip the cream until stiff and spoon it into a piping bag fitted with a star shaped nozzle. Spoon the cooled compote into the bottom half of the choux buns and then pipe a double layer of cream on top of the compote and bottom half of choux, ensuring no compote can be seen.
Top with the streusel top and dust with icing sugar.
The filled choux buns will start to soften, so these are best eaten within 24-48 hours of filling.
The frozen cooked choux pastry will keep for around 2 months, just thaw at room temperature before filling.