Preheat the oven to 350 degrees F. Line 2 baking sheets with parchment paper.

Thoroughly stir the flour, baking soda, salt and cinnamon together in a bowl. Add the oats and stir well. Set aside.

In a large mixing bowl, beat the butter and both sugars until light and creamy. Add the vanilla and egg and beat just until mixed. Using lowest speed of mixer (or by hand), stir in the flour mixture, followed by the raisins and nuts. The batter will be very thick.

Scoop up very generously rounded tablespoons (you’ll be using about 2 tablespoons total) of dough and shape into dense balls. Put the balls on a plate and chill until ready to use or bake immediately.

Bake for 10-12 minutes at 350F. Let cool on baking sheets for about 2 minutes, then transfer to a wire rack.