KYH, since I'm living in a country where most people eat potatoes every day, I am interested in this kind of stuff. I never heard of a potato dish in which sugar was involved, which doesn't mean it does not exist, I would dare make a guess it's scandinavian, but the rose water, that's arabic and they don't eat potatoes. To be frank, sugar and potatoes are a big no for me.
I'm also thinking of the potatoblinis I make with gravad lax. In fact they are small pancakes but without the sugar. Basically it's potato, 20% of that volume flour, an egg, a dash of cream and add milk until you reach a stage where the dough has the consistency of mayo, seasoning. Fried in a pan, they go fluffy and very tasteful even without sugar.
When I read your ingredients and the quantities you use, I'm very sceptical about the measurements. If it were me, I would make these changes;
1 lb potato
¾ lb butter; 250 gram (1/2lb)
½ lb sugar; I would leave that out completely and go for salt and pepper. Maybe some flour instead?
¾ cup milk or cream; I would go to 750 ml since you're using a very big quantity of eggs. This quantity of milk will match the eggquantity. Of course, the eggs will make the dough raise while baking and come down again when cooling.
Juice and zest of one lemon
2 tsp nutmeg; that's an enormous amount, I would go for just a pinch
4 whole eggs
3 egg yolks
2 tsp rose water; that's absolutely too much, a few drops will already be more than enough, that stuff is much too overpowering.