Preheat the oven to 200°C/180°C fan/gas 6. Line a 23cm x 33cm lipped swiss roll tin with baking paper, lightly oiled.

In a large bowl, whisk egg whites with an electric mixer until thick and glossy. Gradually whisk in sugar on low speed, then fold in flour, ground almonds, and coffee.

Pour meringue into prepared tin, spreading evenly. Scatter flaked almonds on top and bake for 8 minutes, then reduce temperature and bake for 20-25 minutes until firm.

Carefully lift meringue from tin using baking paper, cool for 10 minutes, then invert onto another piece of baking paper to cool completely.

Melt dark chocolate in a heatproof bowl over simmering water, then stir in butter and cool for 15 minutes.

Gradually add double cream to the chocolate mix, beating with a whisk. Sprinkle in sea salt and spread over the cooled meringue. Chill for 15 minutes.

Combine double cream, icing sugar, and espresso coffee powder in a bowl, whisking until soft peaks form. Be careful not to over-whisk.

Spread whipped cream over chocolate layer, roll tightly from one edge using baking paper. Wrap securely and chill for at least 3 hours.

Transfer roulade to a plate, drizzle with melted chocolate, and slice to serve.