Beat the butter with the sugar and corn syrup until fluffy, then beat in the flour and baking soda.
Mix in the raisins.
Roll the dough into walnut-sized balls and arrange on greased baking sheets.
Bake in a preheated 375° oven for 15 minutes.
Let set for a few minutes, then lift off the baking sheets with a long metal spatula and cool on a wire rack.