Peel the potatoes and wipe with a wet paper towel.
Grate the potatoes using small or medium size blade. You have to do it quickly (but carefully, watch out for your fingers) to avoid darkening of the potatoes. It will still discolor some, but that’s unavoidable.
Squeeze as much liquid out of potatoes as you can. Don’t worry about making it too dry - egg will bind it all together.
Add salt and egg. Mix well with a spatula.
Pre-heat the butter and olive oil over medium-medium high heat (I use 6 on my 2-10 knob marks) in a pan big enough to fit all the pancakes arranged somewhat loosely.
Next, portion them out onto the pan, using a spoon or cookie scoop (once it feels hot enough) and push the edges in to round it out. Flatten the top with the spatula as well. They should be about 1/4-1/3 inch thick.
Let cook about 6 minutes per side. Depending on your stove and the pan you use , cooking time may vary. Gently lift one on the side to check. It should look crisped, golden brown.
When done, carefully transfer them onto the plate and serve immediately, topped with sour cream and greens. Enjoy!