Preheat oven to 180°C and heat 1tsp olive oil in a non-stick frying pan.
Season duck with pepper then place in hot pan and cook until coloured on each side (approx 1-2 minutes per side).
Transfer duck to a roasting tin and bake in oven for 5 minutes. Transfer to plate, cover loosely with tinfoil. Allow to rest while you make the sauce.
Place roasting tin on stovetop over a medium heat and add the garlic and wine. Simmer, gently scraping the pan with a wooden spoon to deglaze.
Once wine has reduced by half, crumble in stock cube and stir to blend. Remove garlic clove.
Add the blackcurrants and sugar and simmer for a couple of minutes until blackcurrant skins have burst and sauce looks syrupy. Taste and add a little more sugar and/or pepper if necessary - the sauce should be tart but not sour.
Thickly slice the duck breasts and arrange on plates. Stir any juices shed by the duck into the sauce, stir and pour over.
