Butter-rich cookies that go well with sherbet, chocolate mousse, or pudding.
Cream butter and add sugar gradually. Add eggs, and blend well. Sift together flour and baking powder, and add to butter and egg mixture along with orange juice and vanilla. Knead until dough is smooth, adding a bit more flour if necessary. Dough should not be sticky. Pull off pieces the size of walnuts and toll into strips about 8 inches long; form into twists or loose circles. Add water to reserved egg yolk and beat till blended. Brush over twists and sprinkle with sesame seeds. Bake on next to highest rack in oven at 350 degrees F for 15 minutes, or until lightly browned.