Preheat oven to 180° C. Grease a baking pan.
Sieve oats flour, coco power , baking soda, and salt together in a bowl. In another bowl beat melted butter, powdered sugar together until light and fluffy, 3 to 5 minutes.
Now mix condensed milk and sprig vanilla essence into butter mixture until smooth. Gradually stir flour mixture into butter mixture until just combined. Add milk if requied.
Add some chocolate chips. Spread cookie batter into prepared pan.
Bake the cookie cake for 25 minutes. When its done check with toothpick. Cool it completely.
Next using double boiling method melt the dark chocolate. Cool it down and fill in a piping bag. Drizzle the chocolate design and keep it in a fridge to set.
When its done , serve and enjoy.
