In a bowl, mix half of the oil with 1 tsp of the minced garlic and the chilli flakes ( if used).
In a s mortar, crush the walnut kernels with a couple pinches pinches of salt and the remaining garlic into a coarse paste. Transfer the mixture to a bowl.
Add the paprika (if used) then and slowly pour over the oil while stirring constantly. Mix in the coriander. Taste, and season with salt & pepper to your liking. Set aside.
Cut the aubergine (vertically) into half-cm slices. Brush them with the garlic oil, then grill them in a griddle pan, while brushing with more oil.
When they have softened and charred, transfer them to a plate. Put a generous dollop of walnut pesto at one end of each aubergine slice, then roll them up.
Repeat with the remaining aubergine slices. Sprinkle some paprika on top.
Serve them at room temperature.