Whisk together flour, salt and baking powder.
Using electric mixer with paddle attachment beat butter and sugar together until fluffy, about 5 mins.
Add vanilla bean and mix well.
Add eggs and egg yolk. Combine well.
Add the flour mix a bit at a time. Combine until mixed, but avoid over mixing.
Divide dough into 2 separate pieces. Wrap tightly in plastic wrap and chill for at least 30 minutes.
When ready to bake preheat oven to 350º F. Line cookie sheets with parchment paper.
On well floured work surface roll disk out to 1/4 inch thickness.
Cut out with cookie cutter shape of your choice and transfer to baking sheet. To avoid dough sticking to cookie cutters dip them in bowl of flour, shaking off any excess.
Place cookie sheet in freezer for about 5 minutes or refrigerator for 10 mins. This helps the cookies hold their shape and not spread.
Bake 8-10 minutes (just until edges start to brown).
Allow to cool a bit on cookie sheet, then transfer to cooling rack. Decorate with Royal Icing.