Blend all filling ingredients, except poppy seeds, into a smooth mixture in a power blender. Add in the poppy seeds and pulse briefly to blend them in without crushing them (or can stir them into the mixture by hand if you prefer). Transfer this mixture over the prepared crust and smooth out the top. Sprinkle with any desired toppings (except fresh flowers) and freeze for 5-6 hours or overnight. Decorate with fresh flowers prior to serving if using. Thaw the cake out on the counter a few minutes and enjoy!