Prepare the Custard Apple: Peel the ripe custard apples, remove the seeds, and scoop out the flesh into a blender.
Add Ingredients: Add the yogurt, honey, and milk into the blender with the custard apple flesh. If you prefer a colder smoothie, add a few ice cubes.
Blend Until Smooth: Blend on high speed until all ingredients are well combined and smooth.
Taste and Adjust: Taste the smoothie and adjust sweetness or thickness by adding more honey or milk if necessary.
Serve: Pour the smoothie into glasses, garnish with mint leaves if desired, and enjoy immediately.