Heat the 2 tbsp vegetable oil in a shallow saucepan.
Add the chopped onions, garlic and mushrooms.
Cook over a high heat for 10 minutes, to get heat into the dish.
Add the mince, break up well, and cook until it changes colour from red to fawny colour.
Add the 2 Oxo cubes and brown sauce and really mix well.
Add the potatoes and simmer gently for 30 minutes, or until the potatoes are cooked and slightly falling apart.
You can thicken with a little flour and water mixed together.