Approximately 280-300 g pumpkin is boiled and passaged. Transfer the pumpkin in a convenient container and to it add the eggs, the oil, sugar and vanilla sugar (vanilla sugar can be replaced with essence or plain vanilla). Once we mix well with mixer, gradually add flour mixed with baking powder and salt. Ready mix divide into two equal parts. Break the chocolate together with the butter melting it (preferably in a water bath). Add the melted chocolate to one of the two mixtures and mix well. Format muffins rotate spoon with white spoon of brown mixture. Bake in preheated oven at 180C degrees around 25-30minuti. For sure check with a toothpick if the muffins are ready. * Chocolate can be substituted with 2-3 tbsp cocoa, as in this case and miss the butter.