1. Pre-heat the oven to 190C/375F/Gas 5
2. Make the Choux buns:
Line a baking tray with non-stick baking parchment. Use a pastry cutter to mark 12 circles that are 3.5cm/1½in in diameter, with space between them of the same width.
Place a sheet of baking parchment out and crease it in the middle and press out again. Sift the flour into the centre of the crease, add the cayenne pepper and set aside.
Measure the cold water and butter into a small saucepan and heat gently, stirring with a small wooden spoon until the butter has melted. Slowly bring to the boil and then immediately remove the pan from the heat. Tip the flour in, in one go and beat vigorously until the mixture forms into a ball. Allow to cool slightly then beat in the beaten egg to form a smooth glossy paste.
Place a piping bag fitted with a round nozzle into the neck of a tall glass and spoon the choux pastry into it. Lightly spay the prepared baking tray with water and pipe evenly sized balls onto the baking sheet, leaving a space double the size piped between each one. Bake in the oven for approx 10 minutes until golden brown, crisp and risen.
Remove from the oven and reduce the temperature to 160C and pierce the base of each bun with a cocktail stick. Return to the oven to dry out for a few minutes and then transfer to a wire rack to cool completely.
3. Make the tomato glaze:
Soften the sheets of gelatine in a bowl of cold water. Measure the tomato ketchup into a small saucepan and once the gelatine sheets have softened, squeeze off the excess water and add to the pan. Stir over a low heat until a smooth mixture is formed and strain into a bowl through a metal sift and set aside.
4. Make the smoked trout pate:
Place the smoked trout and butter in a food processor and blend until smooth. Add the creamed horseradish, sour cream, pepper and chopped herbs and blend again. Add the lemon juice and pepper to season.
Transfer into a bowl and spoon into a piping bag fitted with a small nozzle and fill each choux bun with the pate.
5. To assemble:
Coat each choux bun with tomato glaze by carefully spooning it over the top with a teaspoon. Place a small sprig of basil on top of each (to resemble a tomato leaf) and leave to set.
For the pastry:
25g unsalted butter, cut into small pieces
Pinch of sugar
Pinch of salt
Pinch of cayenne pepper
35g plain flour
1 large egg, beaten
For the tomato glaze:
3 sheets gelatine
150g tomato ketchup
For the smoked trout pate:
120g smoked trout
100g unsalted butter, softened
1 1/2 Tbsp/40g creamed horseradish
Handful of fresh parsley
Handful of fresh dill
Fresh lemon juice to taste
Salt and pepper to season
Pot of basil