Dissolve the yeast in the beer then add the salt, sugar, and vinegar in a large bowl.
Sieve the flour into the liquid and beat until smooth, then chill in the fridge for 20 minutes.
Heat the cooking oil in a frying pan to 180°C.
Hull the strawberries, cut them in half, and dredge both strawberries and raspberries in flour.
Dip the fruit in the batter and fry in the hot oil until golden and puffed.
Drain the fried fruit on kitchen paper and dust with caster sugar.
Pureé the remaining fruit with sugar and lemon juice using a hand blender, then sieve.
Serve the battered fruit with the prepared coulis and clotted cream.