In the mean time - melt the butter, but stop as fast as it softens, do not over heat it or maybe burn it - you'll lose the taste. Now take an enormous giant big bowl and throw in all of the flour, vanilla sugar ( one sachet ) and some salt. Mix while you are adding milk ( and some mineral water if you'd like ). The name is Biblical in origin as Jacob was the boy of Isaac and Rebekah.
Jacob had 12 boys and a girl who became the predecessors of the country of Israel. The name has about four different alternative forms developed over the last centuries. Most famously noted folks with the name Jacob in todays society are Senator Jacob Javits and actor Jake Gyllenhall.