Place the pumpkin cubes in a saucepan filled with boiling water and cook for approx. 10 min., or until tender. Drain off the water and blend the pumpkin for approx. 30 sec. – into a thick pumpkin purée.
Melt the butter in a saucepan and add the milk. Pour the mixture into a bowl and stir in the yeast. Add the pumpkin purée and the other ingredients (reserve some of the flour for later). Knead the dough well or run in an electric mixer for approx. 5 min. Cover the bowl, for example with the lid of a pot and leave in a warm place to rise for about an hour.
Tip the dough out onto a floured surface and knead thoroughly. Add the rest of the flour as needed. Divide the dough into 16 pieces and shape into rolls. Flatten slightly, then make 6 cuts into the rolls. Place the buns on 2 baking sheet lined with parchment and let them rise again for approx. 45 min. Brush with egg and press a pecan down in the middle of each roll. Bake the rolls in the middle of the oven approx. 15 min. at 175°C (fan oven), then cool on a rack.