Lightly smash the garlic by placing the cloves under a glass or other flat surface and pressing them gently to release their juice and aroma. Use a sharp vegetable peeler to remove long strips of zest from the lemon, avoiding the bitter-tasting white pith underneath.

Combine the olives, herbs, garlic, lemon zest and half the almonds in a large bowl. Add the olive oil, vermouth, juice of half a lemon and black peppercorns, if using. Mix well to completely coat the olives. Cover and let stand in the refrigerator for 6-8 hours. This can also be done overnight.

Before serving, bring the olives back to room temperature, and add the remaining Marcona almonds. Sprinkle with a final pinch of sea salt flakes, which adds a delicate crunch and heightens the flavours.