Incise diamond-shaped skin on duck breasts without cutting the meat. Fry on low heat for breast skin side down until crispy and golden brown. Turn, season with salt and pepper and fry again. Duck should be slightly pink inside. Put the breast and remove to a warm place. Peel the garlic and fry in a pan in which roasted breast, crush with a fork, add the balsamic vinegar. Add raspberry jam and fresh raspberries with sugar, whisk until smooth, add salt and plenty of pepper. Cut the breast into slices and serve with the sauce, sprinkle with mint leaves.