Add your meat & butter to a frying pan and cook on a medium heat.
Once the juices have reduced, add your onion & pepper (and chilli, if using).
Stir around until your onion & pepper have softened a little.
Now add your grated tomato & simmer for a few minutes to allow your beef to cook through.
Add your chopped tomato, oregano & seasoning and stir.
After a couple of minutes, add your salca & around 100ml water.
Stir until your salca has dissolved and simmer until your beef has completely softened.
Add more water if your sauce thickens too much.
Remove from the heat.