Exporting ice cream or Mochi?

I would love to bring back Mochi and Ice cream to Malaysia but I can't seem to find rules regarding this. Can I actually do that and how so because I know you can't carry liquids on the plane so carry-on is out of the option. Help please?

Check in the ice cream
Wrapped everything with string or rope then place in a box. If you have an ice box the ice cream stsys as a solid and you can carry on

it's best if you use dry ice, not sure about customs if they will allow you to take out of japan.

I would love to bring back Mochi and Ice cream to Malaysia but I can't seem to find rules regarding this.

Sure, no problem taking it out of Japan. But you'll need to check Malaysian customs rule regarding importing these items.

Can I actually do that and how so because I know you can't carry liquids on the plane so carry-on is out of the option. Help please?

Yes, you can pack it in dry ice and check it in. Check with your airline, they usually have a limit on the weight of dry ice that can be checked.

If you have an ice box the ice cream stsys as a solid and you can carry on

You'd better check with the airline, as I think it may be considered a liquid even when frozen.