Preheat the oven to 190C, 375F, Gas mark 5. Heat the oil in a pan add the
and garlic and sauté gently until soft.
Add the bacon and mushrooms and cook for 2 minutes then add the capers,
tomatoes and tomato paste. Bring to the boil and simmer for 5 minutes.
Meanwhile, melt the butter in a separate saucepan and blend in the flour.
stirring for 1-2 minutes then remove from the heat and gradually whisk in
milk. Return to the heat, whisking continuously until the sauce comes to the
and thickens. Remove from the heat and season well. Set aside.
Add the tuna fish and seasoning to the tomato sauce. Assemble the lasagne by
a third of the tuna mixture in the base of a 30.5 x 23cm (12 x 9") gratin
cover with 3 sheets of lasagne. Follow this with another third of the tuna, a
of Parmesan and a further 3 sheets of lasagne. Repeat topping with the
sauce and a final sprinkling of Parmesan cheese. Bake for 45 minutes. Serve