When working with the dough, use powdered sugar on your hands instead of flour; these cookies are flour-y enough. The longer you chill the dough, the better it holds its shape. Use unsalted butter, and almost anything other than red currant jelly is too sweet. Mashing the jelly with a fork makes it less likely to bubble up and spill over onto the dough.
Take 3/4 cup softened butter, 1/2 cup sugar, 1 egg yolk, and 1 1/2 cups cake flour. Cream butter and sugar with egg yolk. Fold in flour, knead a little bit, wrap in wax paper, and chill. Roll into 1/2 inch balls, make a small depression in the middle, and fill with jelly. Bake at 325 until golden.
