Cut the aubergine lengthwise into very thin slices - don't worry if some of the slices aren't completely 'full' - it's better to make sure they're nice and thin (ideally about 2mm thick).
Spray a griddle pan (or frying pan, if you don't have a griddle pan) with oil, and cook the aubergine slices until soft - just a minute or so on each side.
Thoroughly spray 3 large ramekins or small bowls with oil, and line with the aubergine slices, pressing into the corners of the dish. Make sure each slice overhangs the edge of the dish by at least a couple of centimetres. Save a few slices back.
To make the filling, add the garlic, spring onions and parsley to a food processor, and blitz until well chopped. Add the spinach and sun-dried tomatoes, and repeat. Finally add the ricotta, pesto, egg, and a pinch of salt and pepper, and blitz to combine.
Add the filling mixture to the three aubergine-lined bowls. You'll need to keep back three slices of aubergine for topping the parcels, but if you have any extra slices, make another layer of aubergine in the middle of the filling.
When the filling has all been distributed, fold the slices of aubergine over the top, and add one more slice to ensure each parcel is well covered.
Place the bowls in the oven and bake at 180°C (Gas Mark 4 / 350°F) for 50-60 minutes, until the filling is firm. Serve warm.