Position oven racks in the upper and lower thirds of the oven and preheat oven to 180℃/160℃ Fan/350℉.
Line 2 baking sheets with parchment paper or silicone baking mats.
In a large bowl, whisk 240 g (2¾ cup) rolled oats, 200 g (1½ cups) plain (all purpose) flour, 1 tsp bicarbonate of soda, and ¾ tsp salt in a large bowl until they are well blended.
In the bowl of a stand mixer fitted with the paddle attachment, beat 165 g (¾ cup) butter and 1 tbsp vanilla extract on medium high speed until blended and creamy.
Add 140 g (¾ cup) dark brown sugar and 90 g (¾ cup) granulated white sugar to the mixer bowl.
Beat until light and fluffly, for about 2 minutes.
Beat in the 2 eggs, 1 at a time.
Reduce mixer speed to low and gradually add the oat mixture.
Then add 200 g (1 cup) chopped white chocolate or chocolate chips.
Scoop the batter, 2 tbsp at a time, onto prepared baking sheets, about 8 cookies to a sheet. I use my smallest ice cream scoop to scoop the batter onto the baking trays.
Sprinkle a few sea salt flakes onto each cookie.
Bake for 12 – 14 minutes until the cookies are golden around the edges but still a bit soft in a centre. Rotate the baking sheets from front to back and top to bottom half way through baking. Do not over bake.
Let cookies cool on the baking sheets for 2 minutes and then use a spatula to transfer them to a wire rack to cool completely.
Wipe clean reusable baking mats or cover the baking sheets with new parchment paper and scoop the remaining dough onto them and bake as before.
Serve the Salted Vanilla Oatmeal Cookies with a hot or cold drink as a tasty snack or a convenient dessert.