Preheat the oven to 350 degrees F (175 degrees C). Grease cookie sheets.

Beat together butter, sugars, eggs, and vanilla in a large bowl with an electric mixer until light and fluffy, about 5 minutes. Combine oats, flour, baking soda, baking powder, and salt in a separate bowl. Add flour mixture, 1 cup at a time, beating batter briefly after each addition. Mix in raisins and cranberries. Drop by spoonfuls onto the prepared cookie sheets.

Bake in the preheated oven until edges are golden, 12 to 14 minutes.