Put the flour into a large bowl, rub in the butter, then stir in salt and yeast. Make a well in the middle and pour in lukewarm milk. Using a wooden spoon, mix to a soft but not sticky dough.
Lightly oil a large bowl. Knead the dough until it is smooth and elastic. Shape it into a round and place in the bowl. Cover with oiled plastic wrap and leave in a warm place for 1-1 1/2 hours, until doubled in size.
Turn out the dough onto a lightly floured work surface and punch down with your fist. Knead for 2-3 minutes, until the dough is smooth and elastic.
Divide the dough into 18 even-sized pieces and shape into balls, folding the sides to the middles to form tight round balls.(Or shape into a rope and tie in a single knot. Or you may roll each piece of dough into a thin strand. Fold in half and twist together, sealing the ends well to form a twist. Last but not least, you may try shaping each piece of dough into a ball or an oval and snipping tops with scissors).
Lightly oil 2 or 3 baking sheets. Arrange the rolls on the baking sheets, leaving enough room between them for the dough to expand, cover loosely with oiled plastic wrqp, and leave in a warm place to rise for 15-20 minutes, until the dough has doubled in size.
Brush the rolls with the beaten egg to glaze and sprinkle with poppy seeds and sesame seeds. Bake in a 450*F. oven for about 15 minutes,until they are well risen and golden. Tap the bottoms to see if the rolls are cooked; they should sound hollow. Leave to cool on a wire rack. Enjoy!