Preheat oven to 350 F (180 C). Line a large baking sheet with parchment paper. Lightly crush the cornflakes into smaller pieces in a bowl. Don't crush them too much though. I prefer to be able to still see the small pieces and not powder. Set aside
Let the butter softens at room temperature for about 30 minutes or until you can easily mash with a spatula. Add icing sugar and mash together until creamy
Add all-purpose flour, cornstarch and raisins. Use your clean hand to mix into a sticky dough
Coat the cookie with cornflake pieces:
Scoop about 10-15 grams or 1 Tbsp of the dough or use a cookie scoop and drop it on the cornflakes. Coat the dough with the cornflakes all over. Place on a baking sheet. This cookie doesn't spread much. You can give about 1/2-inch of space in between cookies
Bake at 350 F for 15 minutes or until the bottom of the cookies are golden brown. Let them cool on the rack for 5 minutes and then transfer to a cooling rack to let them cool down completely. Transfer to an air-tight container