Heat half the butter in the saucepan and add the bay leaf. Add the onion and carrots and saute till wilted.
Add the mince meat and cook for five minutes.
Add the ingredients from green peas to salt and pepper and cook till the meat is done. Discard the bay leaf.
Mash the potatoes while hot. Add in the remaining butter, salt and pepper and mix well.
Preheat oven to 180 degrees.
In a glass dish, spread the mince meat mixture.
Top with the mashed potato and press down. Sprinkle the rosemary all over.
Bake for 30 minutes till the top is browned. Serve warm.
Notes
You can sprinkle some mozarella cheese on top to make it more rich. If you feel your base is more dry, add more water. You can substitute stock + water with homemade or store-bought stock in equal quantity.