Saint Agur crème and blueberry roulade

Preheat an oven to 180°C/gas mark 4 and line a 22x32cm baking tray with baking paper. Use an electric whisk or stand mixer to whisk the eggs and sugar for 3-4 minutes, until it reaches the thick, fluffy ‘ribbon’ stage

Fold in the flour, ensuring it is evenly mixed but doesn’t make the mixture lose its volume, then pour into the lined baking tray and bake for 10-12 minutes. Once cooked, leave to cool completely

While the sponge cooks and cools, prepare the filling. Place the defrosted blueberries in a blender with a squeeze of lemon juice and blitz to a purée. Transfer to a saucepan, bring to the boil for 30 seconds, then pass through a fine sieve into a bowl and leave to chill completely

Once the sponge has cooled, place a clean tea towel onto a work surface and turn the sponge out onto the towel. Carefully peel back and discard the baking paper, then brush the sponge with the boiled Kirsch (if using)

Fold the mascarpone (or crème fraiche), Saint Agur crème and icing sugar together in a bowl, then add half of the blueberry purée – don’t fully mix the two together, so you have a nice contrast of purple and white swirls. Reserve the other half of the purée to serve alongside the roulade

Use a palette knife to spread the filling evenly over the sponge, making sure you leave a 1cm gap from the longer edges and a 5cm gap from one end of the shortest side. Arrange the sponge so the shortest side is facing you, with the 5cm gap facing away from you. Using the tea towel for support, carefully but firmly roll the roulade up, making sure you don’t press too hard and squeeze the filling out

If desired, dust the roulade with caster or icing sugar, then trim the edges. To serve, cut the roulade into 6-8 slices, then divide between plates with a spoonful of the remaining purée