Preheat the oven to 180 degrees. Cut the aubergines into slices, season them with salt and pepper and olive oil and roast for about 40 mins, until they're soft.
Meanwhile, gently heat some olive oil in a big pan and add the whole tomatoes and the basil. Crush a few of the tomatoes down with a fork. Cover with a lid and cook over a low heat.
When the aubergines are cooked, roughly mash them and add the ricotta, sage, egg and salt and pepper. Mix well.
Put a little bit of oil on your hands and shape the mix into little 2 pound coin shaped balls. Roll these in some semolina flour and put on a tray. Keep rolling until all the mixture is used up. When you're done, chill for an hour.
Boil some water and cook the dumplings for about 2 minutes each, until they float. When they're done, scoop them out with a slotted spoon and put them onto kitchen towel.
Add a spoonful of butter to the tomato mixture
Put about 6 dumplings into each bowl. Spoon over the sauce and grate over the parmesan.