Grate zucchini, then transfer onto a small towel and wring the excess liquide.
In a large mixing bowl, combine zucchini, egg, parmesan cheese, salt, pepper, red pepper flakes and garlic.
Cover a rectangular baking sheet with parchment paper and spread the mixture into a square of approx. 1 cm thick.
Bake for 35-40 min at 180°C.
Let it cool down for 10-15 minutes.
Meanwhile, in a small bowl, combine salmon, mascarpone and parsley. Spread the mixture over the zucchini and starting at one of the ends, carefully begin rolling it up into a "log".