Put the raspberries in a small bowl and sprinkle with 2-3 tbsp of sugar. Leave aside. Beat sugar with butter until soft obtain crumbs. Add the egg and vanilla and beat again. Add the milk and beat the mixture until smooth. Sift flour into a separate bowl and mix it with baking powder and salt. Add it to the milk mixture all at once and stir gently just enough to knead the ingredients. Do not put too much because it can cause the muffins to obtain concise. Do not worry if small lumps remain. Will dissolve naturally when baked. Grate the chocolate and add to the mixture. Carefully add the raspberries. Divide the mixture into 12 medium muffin trays, pre-greased and floured or lined with a paper cutter. Bake in preheated 190 C oven for 15-20 minutes. Check whether they are ready with a toothpick. If dry out, you are ready.