Soak the dates 1 cup water in the refrigerator overnight. Strain, reserving the soaking liquid (aka “date juice).
Preheat the oven to 350 degrees F. Line a loaf pan with reusable parchment paper and set aside.
Combine the flax meal with 6 tablespoons warm water in a large bowl. Stir and let set for 5 minutes.
Meanwhile, combine the avocado with the soaked dates in a carafe or small bowl. Blitz with an immersion blender until smooth and creamy.
Add the date-avocado mixture to the bowl with the flax. Then add the discard starter, flour, water, cacao, maca, Dandy Blend, baking soda, baking powder, salt, and date juice stirring after each addition. Mix well to incorporate all the ingredients.
Fold in the chocolate chips, then spread the batter in an even layer in the prepared loaf pan. Bake for 45 to 50 minutes, or until a knife comes out clean when inserted into the center. (I prefer my cake a little more fudgy, so let it be slightly underbaked—i.e., the knife still had a bit of chocolate on it when I tested it.) Let cool for at least 30 minutes.
To make the cashew cream: Strain the soaked cashews and place them in a carafe or bowl with ⅓ cup water. Blitz with an immersion blender until smooth. Add the date juice, coconut oil, and rose powder. Blitz again until the cream is evenly pink throughout. Set in the refrigerator to chill while the cake is baking and cooling, or until ready to serve.
Once the cake is cool, use the parchment to lift it out of the pan. Peel off the parchment, and spread an even layer of the cashew cream over the top. Sprinkle the cake with rose petals, if using.
Store any remaining cake in an airtight container in the refrigerator for up to 1 week. If you use a lighter hand while frosting, store extra cashew cream in a separate jar or container for up to a week.