Cut your bread into small cubes (½" / 12mm) making sure no crusts remain.
Over medium heat, warm your coconut milk and bread pieces in a saucepan until gently simmering.
Once simmering, add your corn starch slurry (and any sugar, if using). Cook 2-4 minutes until sufficiently thickened. (If not thick enough, you can add another ½ Tbsp of corn starch made into a slurry.)
Remove from heat, add rose and orange blossom water (or only one if desired). Allow to cool in the refrigerator for at least one hour.
For smooth (mascarpone-like) ashta, put into your stand mixer bowl and whisk on medium high for 2 minutes or so.
Serve chilled, as a dessert with syrup and chopped nuts, as a topping for fruit, or in pastries.