Preheat oven to 190°C and line a baking tray with parchment paper.
Melt butter in a sauté pan over medium heat until bubbling subsides and butter browns, about 5 minutes. Strain butter through a coffee filter and cool to room temperature.
Beat butter with brown sugar, sugar and egg until smooth. Stir in vanilla. In a separate bowl, stir oats, flours, cinnamon, baking soda and salt to combine.
Add oat mixture to butter mixture and blend. Stir in choice of chocolate chips, raisins, walnuts, and/or coconut.
Drop by spoonfuls onto prepared tray and bake in the center of oven for about 12 minutes, until browned. Let cool for 5 minutes, then gently remove from tray onto a rack to cool completely.