Heat the milk in a small saucepan. Remove from heat before it boils. Mix flour, oats and barley, 100 g of Parmesan, parsley, egg and milk to create a homogenous thick mass.
If necessary , add more oats and barley, and let the dough rest 30 minutes. Use dough to form elongated cylinders approximately 1.5 cm thick and cut into 2 cm long pieces. Place pieces on a dish towel and lightly flour them.
In a pot , bring lightly salted water to boil and cook the gnocchi in batches for 15 minutes.
Drain and mix the gnocchi with the butter and remaining Parmesan.