Nice and simple...
Spuds
Onions
Butter
Salt
Semolina
Baking Parchment
Take 3/4s of the spuds and boil then mash with the butter and salt
The remaining quarter dice fairly small and briefly boil - they should still have some bite
Finely dice the onion - upto you if you cook it off a little first - I dont
Mix all together and form into whatever shape you want, I do kinda trinagles, kinda rounds, kinda squares but as long as they are all of uniform shape and size it doesn't matter
Lightly dredge in the semolina and then bake in the oven on the parchment turning every now and then until cooked - about 20 mins or so at ~200°C
Note - These also make good croquettes, rolled in those day-glo orange breadcrumbs!