Massaman (Muslim) Curry with beef and potato

Like all good curries, you can put whatever combination of meat and veges. This one goes best with beef and potatoes but pork is exceptional as well.
3 Tablespoons of massaman curry paste
2 tins of coconut milk (700-800 ml)
1 kg total of beef and potato cut into 2cm pieces. Eg. 750g of beef and 250g potato is good. You might want half and half.
2 teaspoons of sugar
1 teaspoon salt
75g roasted peanuts
1 teaspoon of lemon juice
150g of small pickling onions or a large onion quartered with the top intact so it doesn't fall apart.

In a saucepan or large wok place the curry paste and 1 cup of coconut milk and stir over a low heat simmering for a few minutes to release the aroma and flavours. Add the beef until it starts to cook and is well covered with the liquid.
Add another cup of milk and simmer for 20 minutes. Add potatoes and simmer for another 15 minutes until both the meat and potatoes are tender.
Pour in the remaining milk and other ingredients. Cook until the onions are frim but cooked through. Taste to see if extra juice, sugar or some fresh chilli is needed. Serve with rice and some steamed veges.