Pre-heat oven to 200 degrees
Cut the onions in half, leaving the paper on. Rub the cut side with oil and place cut side down on some baking paper on a baking tray in the oven and cook for 15 min. Take out and let cool.
In a bowl, mix together the ricotta, feta, and baby spinach and nutmeg with 3 tbsp of olive oil, set aside or put into a piping bag.
Roughly chop the garlic and in a medium pot, place the other 3 tbsp of olive oil along with the garlic and rosemary. Cook for 5 minutes until aromatic and soft. Pour in the tomatoes and cook for another 10 min then add the stock and basil leaves along with the caster sugar. Mix all together, pour into a 12 inch by 6 inch baking tray.
Peel the petals out of the onion skin and place cut up on the board. With the ricotta mixture, spoon a teaspoon or pipe in some of the mixture then roll up so it holds a pointy cannelloni shape. Place one next to the other until the baking tray is all filled.
Place in the oven and cook for 10 minutes. Take out and rest for 10 minutes for everything to set and cool.
Serve with a side of couscous or rice.