Heat a large frying pan over a medium heat. Add the oil and gently cook the onion with a pinch of salt for 4-5 minutes or until soft and translucent. Add the garlic and continue to cook for 2 minutes.
Crumble in the sausagemeat and fry until coloured on all sides. Add the tomatoes and vegetable stock
season with a pinch of salt and pepper and turn down the heat. Gently simmer for 10 minutes while you make the white sauce.
Melt the butter in a saucepan. Add the flour and stir to mix. Cook over a medium heat for 2-3 minutes
or until the mixture has taken on a biscuit-coloured appearance. Slowly add the milk
bit by bit
whisking as you add to prevent any lumps from forming. Season with salt and pepper and bring to a simmer. Cook for 5 minutes to thicken slightly then remove from the heat.
Meanwhile cook the penne in a pan of salted boiling water according to the packet instructions. Once cooked
drain and pour into the pan with the sausage and tomato mixture. Mix well. Pour this into a medium-sized ovenproof baking dish. Pour over the white sauce and bake for 15-20 minutes
