Preheat the oven to 300 F. Line a greased cookie sheet with parchment paper.

Whisk together the sugars, flour, salt and baking powder. Add the grapeseed oil, the vanilla and the rainbow sprinkles.

The mix will be crumbly; spread it out over the prepared cookie sheet in a mix of small bits and clumps the size of dimes.

Bake for about 20 minutes, stirring at the 10 minute mark so it browns evenly. Transfer to a plate to let cool completely. Keep the pan lined with parchment so you can make the bark on it.

Reserve a small handful of the white chocolate and melt the rest in the microwave in 30 second increments, stirring. When the chocolate is almost fully melted, add the reserved chocolate and stir until smooth.

Spread the chocolate in a thin, even layer in the parchment lined pan. Sprinkle the cookie crumbs over the chocolate. Set the tray in the freezer.

Set the butter in a microwave safe bowl and heat it until it’s partially or half melted. Add the sugars and whisk until the mix is light, about 2 minutes.

Add the vanilla, salt, baking soda and egg whites then whisk for another 2 minutes until light and fluffy.

Sift in the cocoa if lumpy and add the flour, stir with a rubber spatula until the dough is well mixed. Fold in the birthday chocolate bark.

Cover the dough with plastic wrap and set in the fridge overnight.

Prepare two greased cookie sheets with parchment paper. Scoop cookie dough into rounds of 1.5-2 tablespoons of dough and place onto the prepared sheet. Leave about an inch border around the dough as these will spread. Add more birthday bark to the top of the cookie dough or roll in sprinkles if desired.

Store in an airtight container.