Chard and Ricotta Cannelloni

I had a bag of mixed chard leaves from the Riverford box - ruby, golden and green.  They were quite small with not much stem, so I had no qualms about throwing away some of the stems, although I would normally want to use them too.  The blanched leaves were chopped finely and mixed with ricotta, nutmeg and grated Parmesan.  I use lasagne sheets rather than cannelloni tubes, cooking them for a few minutes to soften and drying on kitchen paper.  Marcella Hazan's tip is to spread the filling all over the sheet of lasagne and then roll up, rather than having a wodge of filling in the middle and several layers of pasta round it.  This makes for a much lighter finish.  Place the rolls on a layer of chopped, skinned fresh tomatoes, and then top with a simple bechamel sauce and more Parmesan.  Forty minutes in a medium oven, until all is tender and bubbling with a golden cheesy crust, makes for a most scrummy dinner.  Use spinach if you don't have chard.