Pour the boiling water into the blender. Add the gelatin.
Cover the blender, being sure to hold the lid down to prevent the lid from popping off because of steam, and blend at low speed until the gelatin is completely dissolved, about 30 seconds.
Combine the cold water and ice cubes to make 1-ΒΌ cups. Add to the gelatin in the blender and stir until the ice is partially melted.
Add the yogurt. Cover and blend at high speed for 30 to 45 seconds.
Divide the mixture evenly between 5 dessert glasses, bowls or ramekins. Refrigerate until set, about 30 minutes.