Slice the sausage and asparagus (chop woody ends off) into small cubes. Cut the zucchini in half lengthwise, scoop out the seeds then grate it.
Cook the chorizo asparagus, zucchini
Place a frying pan over medium heat, add a bit of olive oil, chorizo, asparagus and grated zucchini. Cook for about 3 - 5 minutes, stirring occasionally. Remove from the heat and let it cool. Preheat the oven to 190°C / 375°F.
Combine into a delicious filling
In a bowl combine mascarpone or ricotta and an egg yolk, using a spatula. Add the chorizo and vegetables. Season to taste with nutmeg, salt and pepper. This is your cannelloni filling.
bake and serve
To assemble, drizzle the base of your baking dish with one tablespoon of olive oil. Pour in the tomato passata (or canned tomatoes). Spoon the filling into the cannelloni tubes using a tablespoon and lay on top of the tomato passata. Repeat with the remaining filling. Add the freshly grated parmesan cheese over the cannelloni. Bake for 40 minutes at 190°C / 375°F. Remove from the oven, let the cannelloni cool for about 10 minutes, then top with fresh basil and serve.