Start with the garlic:

Place the garlic clove in a mortar with a pinch of coarse salt and pound into a smooth paste.

Add the nuts:

Add the toasted pine nuts and crush until coarsely ground, retaining some texture.

Add the greens:

Gradually add the basil leaves in batches, grinding each time until the leaves are broken down and release their oils.

Incorporate the cheese:

Stir in the grated Parmesan with the pestle until the mixture begins to come together.

Finish with the oil:

Add the black currant wood oil and mix until the pesto is creamy but still has some texture. Taste and adjust with salt and pepper.