Spread half the tomato sauce in a 13 x 9-inch (33 x 23 cm) baking dish. Cover with a layer of noodles. Add a third of the béchamel sauce and 1 cup (100 g) of mozzarella cheese. Cover with another layer of pasta, the remaining tomato sauce and the feta cheese. Add another layer of noodles, then a third of the béchamel and 1 cup (100 g) of mozzarella cheese. Finish with the remaining noodles, béchamel and mozzarella cheese.