Heat the oil in a deep heavy-based pan until a breadcrumb sizzles and turns brown when dropped into it. (CAUTION: Hot oil can be dangerous. Do not leave unattended.)
For the stuffed courgette flowers, mix the ricotta, lemon zest and juice together in a bowl. Season well with salt and freshly ground black pepper.
Carefully spoon equal amounts of the ricotta mixture into each of the courgette flowers. Be careful not to overfill the flowers or they won't close.
Gently squeeze the petals of each flower back together to enclose the ricotta mixture.
Dredge each stuffed courgette flower in some plain flour.
For the batter, mix together the flour, bicarbonate of soda and salt in a clean bowl.
Gradually add the water, whisking well to form a batter.
Dip the stuffed courgette flowers into the batter and transfer to the hot oil to deep-fry for 3-4 minutes, or until golden-brown. Remove from the oil with a slotted spoon and drain on kitchen paper.
For the salad, place the mint, lemon juice and crème fraîche into clean bowl and mix well.
Add the fennel and stir gently to coat.
To serve, place equal amounts of fennel salad onto each plate and top with a deep-fried courgette flower.