Ingredients:
6 medium potatoes (or 5 large potatoes)
2 or 3 large onions
120ml oil (or 115g butter, melted)
150g Cheddar cheese, grated (or 150g dry Bryndzia [sheep's milk cheese], crumbled)
2 tsp salt
2 tsp freshly-ground black pepper
Method:
Peel and quarter the potatoes, place in a pan then cover with water, bring to a simmer and cook until soft. Meanwhile, melt the butter (or heat the oil) in a separate pan and when hot add the onions and cook until golden. Drain the potatoes then rice them before mixing with the onions and cheese.
Season to taste with salt and freshly-ground black pepper and stir to mix thoroughly before setting aside to cool (stir occasionally as the mixture cools). The mixture can be used immediately and can even be refrigerated for several days before use (but you cannot freeze it). Traditionally this is used as a filling for Ukraininan noodle dumplings, vareniki.