Preheat the oven to 180’C
Roast the pepper, tomatoes and squash in the oil for 25-30 minutes, stirring half way through.
In a large saucepan heat a splash of oil and fry the onions until soft.
Add the mince and garlic and continue to stir the mixture until the mince has browned.
Add the oregano, Worcester sauce and the vinegar and cook off until most of the liquid has soaked into the mince.
Pour in the stock, tomato puree and the roasted veg; give it a good stir and then once boiling reduce the heat and simmer for 15-20 minutes, until the sauced has thickened. Taste along the way and add some salt and pepper to your fancy.
Once the mince is cooked add the peas and the sweetcorn.
In the meantime, cook the potato and celeriac in salty boiling water for 15-20 minutes, or until soft enough to mash.
Drain the water and put the potato and squash back in the pan over a low heat to get rid of any excess moisture.
Beat the potato and celeriac together with the butter and a splash of milk if a little dry, until you have a smooth and creamy mash. Add a good twist of salt and pepper.
In an oven proof dish, spread the meat layer on the bottom and then top with the potato.
Grate some parmesan cheese on the top and bake in the oven for 35-40 minutes, until the top is lovely and crispy.
Serve with seasonal vegetables or a lovely crisp salad.