Preheat oven to 400 degrees F. Butter 8 - 9 of the wells of a cupcake pan - preferably nonstick. \tIn a medium mixing bowl whisk the eggs then whisk in the sour cream. Mix in both cheeses and the chives. \tTaste the potatoes and season them with salt and pepper if needed. Add them to the bowl and mix well. \tSpoon them into the pan filling the cups just to the top or a little below. \tBake 25 - 35 minutes until they pull away from the sides of the cup and are golden brown all over. \tRemove from oven and let them cool 5 minutes in pan. Turn them out onto a platter. Serve with sour cream.