This was a 4:30pm lunch.
I added shiso-ume paste to the mentsuyu (noodle dipping sauce) and it was really tasty. Give it a try.
Two servings of soumen, cooked and chilled
1 1/2 small ripe avocados
Shiso ume paste to taste
While the noodles are cooking, mash the avocado. Add shiso ume paste slowly until you have a strength you like. Toss the noodles in the sauce and serve. This can be completed in ten minutes if you time it right.