Preheat the oven to 350°F Lightly grease ( or line with parchment) two baking sheets.
In a large bowl, cream together the butter, oil and sugar. Add the egg, beating until fluffy, then beat in the sour cream and vanilla. Stir in the currants and oats.
In a seperate bowl, mix together the baking soda, cinnamon, salt and flour. Add this mixture a cup at a time to the oat mixture, beating well after each addition. Stir in the nuts. Let the dough rest for 30 minutes.
Using a medium cookie scoop drop the dough onto the prepared baking sheets. Bake the cookies for 12 minutes or until they're light brown. Remove them from the oven and transfer to a rack to cool.