Cook the potatoes in salted water till tender.
Heat a pan and melt 4 tablespoons of butter.
Saute onions in butter until tender, over medium heat.
Add the vegatables according to their cooking time.
Once the vegetables are tender, add minced meat, worcesterchire sauce and the stock and mix well.
Add salt and pepper.
Cook, uncovered, over low heat for 10 minutes, adding more stock/broth as necessary to keep the mixture moist.
Switch off heat.
Mash potatoes in a bowl with remainder of butter, season to taste.
Spread the meat mixture in a baking dish.
Spread the mashed potatoes evenly on top. You can use the fork to make some designs in the potatoes. You can pipe in the potato mix as well.
Bake in a preheated oven at 200C for about 30 minutes or until bubbling and brown.