Preheat the oven to 175°C or 360°F
Sift flour and baking soda into a bowl, then whisk in salt.
Cream together butter and sugars, then add the egg, vanilla extract and olive oil. Mix until combined.
Add the dry ingredients and mix on a low speed to start, then increase to a medium-high until just combined.
Break up ¾ cup of smarties and mix them into the dough using a spatula.
Line a baking tray and divide the dough into 12 equal portions. Approx 2 tablespoons. Roll them into balls and place them on the tray, allowing room for them to spread.
Slightly flatten with your fingers, then add a few smarties on top. Place in the oven and bake for 15 minutes or until the edges are golden brown.
Remove from the oven, add more smarties, and then place on a cooling rack to cool.