Ingredients  
400g pasta, fusilli or penne 
50g butter 
50g plain flour 
3 tbsps tomato puree 
400g tin of chopped tomatoes 
250ml full-fat milk 
280g cheddar, grated 
1 x 160g tin of tuna 
200g sweetcorn 
Salt 
Freshly ground black pepper 

Method  
Preheat the oven to 190c. 

Put a pan of heavily salted water on to boil. Put the pasta into the boiling water and cook according to the package instructions, this will be somewhere between 10 and 15 minutes. 

Meanwhile melt the butter in an oven proof dish (big enough to take all of the sauce), then stir in the flour and cook out for 1 minute, stirring all the time to stop it catching. Add the tomato puree and stir over the heat for 1 more minute.  Add the milk gradually and stir until it is thoroughly combined.  Cook for 3-5 minutes stirring the bottom the whole time until the sauce is thick.  Be patient with this, if it’s not thick at this point, carry on cooking for a few minutes longer. 

Add the tomatoes to the sauce, season with salt and pepper and cook over a low heat for 5 minutes or so until it is nice and glossy.  Turn off the heat and add three quarters of the cheese stirring until melted. Turn the heat back on low if the cheese doesn’t melt with the residual heat. If your sauce is very very thick then add half a ladle of the pasta water and stir through. 

Just before you drain your pasta, take a cup of the pasta water out and put to one side. 

Put the sweetcorn and the pasta into the sauce and thoroughly stir to combine.  If the sauce looks too thick then add a little more of the pasta water until it slackens and coats the pasta nicely.  You might not need the pasta water so just see how you go.  Add the tuna and very gently stir through so you don’t break it up too much.  Check for seasoning and add more salt if needed and a good grind of black pepper and stir through.   

Top with the remaining cheese and put into the oven for 20 minutes until the cheese is golden.