Cut off the stems of the shiso leaves and slice them thinly.

Make a cut in the mentaiko and extract the contents, reserving a small portion for topping.

Place the frozen udon in a microwave-safe container, cover loosely with plastic wrap, and heat according to package instructions. Rinse with cold water and drain.

In a bowl, mash the silken tofu until smooth. Add the mentaiko and the remaining tofu cream ingredients, mixing well.

Add the prepared udon to the tofu cream mixture and mix well.