This is a bit of a job — but great. You can do it all in one go, or cook the mince the day before and make the crepes in the morning with the tomato sauce. Then all you have do is make up a béchamel, assemble it all together and bake. If not, I find it quite satisfying to put the whole thing together in a morning. Your baking dish needs to be about 30 × 20 cm (12 × 8 inches) and about 6 cm (2½ inches) deep so that two lines of filled crepes will fit together. Otherwise, it starts to get quite fiddly if you have to trim the crepes to fit your dish (although they do look very smart that way).