Preheat oven to 350F and line a cookie sheet with parchment.
In a small bowl add butter and sugar and beat until light and fluffy.
Add flour, baking powder, pinch of salt (and drop of vanilla if you have it), combine into cookie dough. If this is too dry add 1/2 tsp water/milk at a time until it is combined.
Fold in oats and raisins.
Scoop onto the cookie sheet (sprinkle coarse sea salt if you like) and bake for 15 minutes until golden around the edges.