For the aubergine fritters, heat the oil in a deep fat fryer to 190C or half-fill a heavy-based pan with vegetable oil and heat until a breadcrumb sizzles and turns brown when dropped into it. (CAUTION: hot oil can be dangerous; do not leave unattended.)
Place a slice of aubergine onto a clean work surface. Season well with salt and freshly ground black pepper, then top each aubergine slice with a slice of mozzarella. Season once more with salt and freshly ground black pepper, then sprinkle over enough dill to cover the mozzarella.
Top with another slice of aubergine to form a stack, then press down well. Repeat with the remaining aubergine, mozzarella and dill until all the aubergine slices, cheese and herbs are used up.
Place the yeast, sugar, vinegar and beer into a large bowl and whisk together until smooth and beginning to bubble. Whisk in the flour to make a thick batter. Season, to taste, with salt and freshly ground black pepper.
Dip all the aubergine and mozzarella stacks into the batter. Coat well, then carefully lower them into the hot oil, in batches. Fry for 1-2 minutes on each side, or until golden-brown and cooked through. Remove from the pan with a slotted spoon and set aside to drain on kitchen paper. Season, to taste, with salt.
For the aubergine 'caviar', preheat the oven to 200C/400F/Gas 6. With a sharp knife, cut slits into the aubergines. Press pieces of the rosemary sprigs and garlic slices into the slits.
Place the aubergines into a roasting tray and roast in the oven for one hour, or until soft. Remove and set aside to cool slightly.
Scoop the aubergine flesh out of the skins with a spoon and place into the bowl of a food processor. Blend to a purée, then add the lemon juice and season, to taste, with salt and freshly ground black pepper.
For the salad, place the salad leaves and dill into a bowl. Whisk the Dijon mustard, vinegar and olive oil together in a separate bowl. Add this dressing to the salad leaves and mix well.
To serve, place a spoonful of aubergine 'caviar' onto each plate. Stack two aubergine fritters on top and pile the dressed salad alongside.