Dissolve the yeast in the beer and add in the salt, sugar and vinegar together into a large mixing bowl.
Sieve the flour into the liquid and beat till smooth and creamy. Place in the fridge for at least 20 minutes before use.
Heat the oil in a frying pan to 180C/350F/Gas 4.
Hull the strawberries and cut in half. Dip the strawberries and raspberries in some flour shaking off the excess.
Add the fruit to the batter, remove and drain off any excess and place directly into the hot oil and fry until golden and puffed up.
Drain on kitchen paper and dust them with caster sugar (a little finely ground black pepper added to the sugar is a nice twist).
Make a coulis from both fruits pureéd together with caster sugar and lemon juice, using a hand blender. Pass the coulis through a sieve to remove the seeds.
Serve the fruits with the coulis and either a dollop of clotted cream or crème fraîche