Make the sweet-and-sour sauce: Heat the oil in a saucepan over medium heat. Add the garlic and cook until lightly browned, about 3 minutes. Add the pine nuts and currants and cook, stirring, until the pine nuts are lightly browned, about 2 minutes. Stir in the vinegar, honey, and chocolate and bring to a boil. Simmer the sauce until thick and syrupy, 3 to 5 minutes, whis