Combine the flour and sugar. Put the butter, milk and 100ml cold water in a pan.
Heat gently to melt the butter, then slowly bring to the boil.
Off the heat, quickly add the flour and sugar, whisking with a handheld electric whisk until the dough comes away from the sides of the pan.
Leave to cool for 10 mins, then gradually add the egg, whisking well between each addition, until glossy, with a dropping consistency (you might not need all the egg).
Preheat the oven to 220°C/fan 200°C/Gas 7.
Grease 2 large baking trays and sprinkle with a little water.
Transfer the dough to a large piping bag fitted with a 1.5cm plain nozzle and pipe éclairs, about 8-10cm in length, onto the trays.
Put in the oven and immediately reduce the heat to 200°C/fan 180°C/Gas 6.
Bake for 20 mins until risen, then, using a serrated knife, carefully split each éclair horizontally.
Replace on the trays, (cut-side up) and bake for 5 mins or until crisp. Transfer to a wire rack until cool.
For the filling:
Put the cream in a bowl with 3 tbsp of the cordial and 2 tbsp of the gin.
Whisk until thick, then cover and chill.
Put the conserve in a pan with the remaining cordial and gin. Heat gently, stirring until smooth, then bring to a simmer.
Turn off the heat. Put the berries in a heatproof bowl, pour the hot jam mix on top. Set aside to cool completely.
To assemble, spoon the cream into a large piping bag fitted with a 1.5 cm star nozzle.
Pipe into the bottom half of each éclair.
Top with the strawberries, spoon over a little jam syrup, then sandwich together.