On high heat, boil water. Once boiling, and some salt. Meanwhile, using basmati rice, rinse very well. Add rice to boiling water and set timer for 7 minutes from the time you put it in. Drain, do not rinse. Thinly and evenly slice one russet potato.
On medium high heat with oil at bottom, place sliced potatoes. Season tops with salt, pepper, and cumin. Once sizzling, add rice. Do not pack the rice. Turn heat to low. Add butter to top. Place clean towel then cover with lid. Set timer for 45 minutes.
Take few slices of saffron and grind. Mix with a little water. Once timer done, remove lid. Take out a few spoons of rice, add to saffron.
Spoon out rice. Top with colored rice and place potatoes at side. Serve.