From Sera the steep relentless climb up to the yellow-walled Sera Ütse retreat takes at least an hour (look up and see it high on the cliff above Sera; if that doesn’t put you off, you’ll be fine!). Sera Ütse was a retreat used by Tsongkhapa (his drub-puk , or meditation cave, can be visited) and is currently home to two monks.
Take the path towards the Chöding hermitage and branch off to the left before you get there, climbing the ridge via a switchback path until you reach the yellow building perched high above the valley. You can also reach the retreat directly from Pabonka’s Tashi Chöling hermitage, but trailfinding is slightly harder.