In a heat-safe mug or teapot, pour hot water over the kombu and let steep for 5 minutes.
Remove the kombu and add matcha powder. Whisk until frothy and dissolved.
Add the ginger slices and gently muddle the umeboshi plum into the drink.
Let sit for another 2–3 minutes before sipping.
Optional: Stir in honey or agave to soften the sourness.
Notes
Adjust the intensity of the umeboshi by starting with half a plum.Drink warm or chill over ice for a refreshing version.Not suitable for people with iodine sensitivity or those avoiding caffeine.