Preheat the oven to 180¢ªC.
Cook the potatoes in boiling, salted water until they are soft.
Drain and mash them with the milk and butter.
Season to taste with salt and pepper.
Meanwhile, heat the oil in a frying pan over a medium heat.
Add the onion, garlic and mince and cook for 5 minutes, stirring, or until the mince is brown.
Add the celery and carrot and cook for a further 3 minutes.
Add the recipe mix and 1 cup of water.
Simmer for 3-4 minutes or until the sauce thickens. Remove from the heat and add the peas.
Place the mince into an 8-cup capacity oven dish. Top with the mashed potato and rough up the surface of the potato with a fork.
Bake in the preheated oven for 30 minutes or until the potato is golden.