Line 2 large baking trays. Place the butter and sugars in a large bowl and cream together until smooth.
Add the egg and Vanilla Extract and beat into the mixture until all combined. Sift the flour and Bicarbonate of Soda on top and fold into the mixture to create a dough.
Add chopped White Chocolate and 1-2 tbsp sprinkles – we used the strands as they hold their colour well whilst baked, stir into the cookie dough.
Divide the cookie dough into 16 equal pieces and roll each pieces into a ball. Pour the sprinkles onto a plate and roll each cookie dough ball in the sprinkles to coat. Place the cookie dough balls on the prepared baking tray spaced slightly apart and then chill in the fridge for 30 minutes.
10 minutes before baking preheat the oven to 190°C/170°C/Gas mark 5. Once chilled place the cookie dough balls into the oven and bake for 10-15 minutes. The cookies will still be soft once baked; they will firm up whilst cooling. Leave to cool on the tray to cool for 10 minutes then transfer to a wire rack to cool completely.