1Preheat the oven to 325F. In a large bowl, beat the butter and brown sugar for a few minutes, until pale and fluffy. Beat in the eggs and vanilla. It may look separated - that's OK.
2Add the flour, oats, oat bran, baking soda, baking powder and salt; stir or mix on low speed until almost blended. Add the chocolate, nuts and seeds and stir just until combined.
3Drop 1/3 cup scoops onto a greased or parchment-lined baking sheet; flatten each to 1/2-inch thick with your hand. Bake for 20 minutes, until pale golden around the edges and set, but still soft in the middle. Transfer to a wire rack to cool.