Cook the potatoes separately
Cut Yukon potatoes into chunks.
Cut sweet potato into similar‑sized chunks.
Boil each in separate pots of salted water until very tender.
(If cooked together, the sweet potato will bleed color.)
While the potatoes are cooking, heat up the oil in a small pan and add the fresh herbs when the oil is quite hot. Let the herbs infuse the oil for about 1 min then set it aside.
Drain the potatoes well when they are just fork tender + rough mash the potatoes separately
Mash each one in its own bowl with:
Salt
Pepper
Keep the texture rustic, not smooth — this helps the marbling.
Create the marble
In a serving bowl, add large spoonfuls of Yukon mash and sweet potato mash.
Use a spoon or spatula to fold 2–3 times only.
Just folding, not mixing
You’ll get beautiful ribbons of gold and orange.
Finish
Drizzle with the infused olive oil.
Add more flaky salt if required
Optional: sprinkle paprika or Aleppo for warmth.