Add the silken tofu to a blender and blend until completely smooth.
In a large microwave-safe bowl, whisk together the glutinous rice flour, corn starch, and sweetener.
Pour in the blended silken tofu and mix until a smooth, thick batter forms.
Cover the bowl with cling wrap and poke a few small holes in the top to allow steam to escape.
Microwave for 2 minutes, then remove and stir well. Return to the microwave for a further 2 minutes, or until a soft, stretchy dough forms. Allow the dough to cool for at least 5 minutes before handling.
Lightly dust your work surface with corn starch and divide the mochi into 8 equal portions.
Roll or gently stretch each portion into a thin round. Place the mochi wrapper into a small bowl to help hold its shape.
Add your Greek yoghurt and fruit filling to the centre. Fold the edges over the filling and pinch together to seal, shaping into a ball. For a higher filling-to-mochi ratio, trim away any excess dough with scissors after sealing.