Close the gate, walk towards the Grottini boulders but just before entering turn right and follow a faint trail through the grass just outside the forest.
After a minute or so, when your path is very faint, you see a cut in the forest on your left with a trail going straight uphill (finding this is the crucial crux of the approach).
Walk uphill until you find a T intersection. Turn left and up.
Now you are walking on a good wide trail snaking uphill.
You find another fork when you're almost on top of the hill. Turn left and if you search between the bushes you will find Blocco di Franz.