Peel the potatoes and cut them into bite-sized pieces.
Finely chop the onion and garlic.
Heat the oil in a heavy-based pan, then soften the onion. Add the garlic and stir for one minute.
Add the paprika and potato pieces, stir again for a couple of minutes.
Pour over the stock and tinned tomatoes.
Bring to the boil and cook at low temperature for 15 minutes.
Stir in the drained beans, and cook for another 5 minutes.
Switch off the heat. Stir in the lemon juice and the chopped parsley.
Taste is, then adjust the seasoning to your liking.