Melt the butter on low heat in a saucepan. Beat in the sugars with a wooden spoon until well-blended. Add the egg and vanilla and beat again. Sift the flour, soda, and spices together in a bowl. Stir flour mix into egg mix, then stir in the oats and the walnuts or raisins. Cover and refrigerate for one hour.
Preheat oven to 350º F. Drop by rounded teaspoonfuls onto a generously greased baking sheet, about 2 inches apart. Flatten each cookie with a spatula to be about 1/3 inch thick. Bake until golden brown, about 12-15 minutes. Cool on a wire rack.